Agronomy

2023

Jump to: 2022, 2021

8 pages, 1552 KiB

Open AccessBrief Report

Elevated Ripening Temperature Mitigates the Eating Quality Deterioration of Rice in the Lower Grain Position Due to the Improvement of Starch Fine Structure and Properties

by Yajie Hu, Yi Xu, Qin Cai, Enwei Yu, Haiyan Wei, Ke Xu, Zhongyang Huo and Hongcheng Zhang

Agronomy 2023, 13(12), 2944; https://doi.org/10.3390/agronomy13122944 - 29 Nov 2023

Viewed by 888

Abstract

Elevated ripening temperature (ET) impacts rice grain quality. In this study, two rice varieties were investigated to evaluate the characterization of starch fine structure and grain eating quality under ET conditions. Rice exposure to ET increased the proportion of large-sized granules and starch [...] Read more.

Elevated ripening temperature (ET) impacts rice grain quality. In this study, two rice varieties were investigated to evaluate the characterization of starch fine structure and grain eating quality under ET conditions. Rice exposure to ET increased the proportion of large-sized granules and starch granule average size, regardless of grain position. Compared to normal temperature (NT), the amylose content (AM) in the upper grain position (UP) exhibited a significant increase under ET, whereas the contrary results showed a decrease in the lower grain position (LP), and the proportion of shorter amylopectin chains increased under ET in UP or LP, whereas the proportion of long amylopectin chains decreased, resulting in a higher starch gelatinization temperature and enthalpy under ET. For grain position, compared to LP, UP had higher AM and a higher proportion of long amylopectin chains, leading to higher gelatinization enthalpy under ET. For eating quality, we found that ET deteriorated the eating quality of rice compared to NT, and UP had higher eating quality than LP under NT; however, there was a comparable eating quality between UP and LP under ET. Hence, elevated grain filling temperature mitigated the eating quality deterioration of rice grain in LP due to the lower AM and gelatinization enthalpy and the higher proportion of shorter amylopectin chains. Full article

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19 pages, 2259 KiB

Open AccessArticle

The Key Physiological and Biochemical Traits Underlying Common Bean (Phaseolus vulgaris L.) Response to Iron Deficiency, and Related Interrelationships

by Khawla Nsiri and Abdelmajid Krouma

Agronomy 2023, 13(8), 2148; https://doi.org/10.3390/agronomy13082148 - 16 Aug 2023

Cited by 4 | Viewed by 1383

Abstract

Iron deficiency is a worldwide nutritional problem affecting crop production. In Tunisia, this mineral disorder hampers the growth and yield of the major crops due to the abundance of calcareous soils that limit iron availability. The common bean is one of these crops [...] Read more.

Iron deficiency is a worldwide nutritional problem affecting crop production. In Tunisia, this mineral disorder hampers the growth and yield of the major crops due to the abundance of calcareous soils that limit iron availability. The common bean is one of these crops suffering from lime-induced iron chlorosis. The exploration of the variability of common bean responses to iron deficiency allows us to screen tolerant cultivars and identify useful traits and indicators for further screening programs. To this end, two common bean cultivars (coco blanc, CB, and coco nain, CN) were cultivated hydroponically in standard nutrient solution (control) or nutrient solution deprived of iron (stressed). Analyses were reported on plant growth, photosynthetic pigments, photosynthesis, iron distribution, H-ATPase, and Fe-chelate reductase (Fe-CR) activities; important indicators were calculated; and convenient correlations were established. Current results demonstrated that iron deficiency stimulated specific symptoms of iron chlorosis on young leaves that were more precocious and severe in CB than CN. Spad index and chlorophyll pigments measurement confirmed these morphological changes and cultivar differences. Net photosynthesis (Pn) showed the same scheme of variation, with a significant decrease in Pn while respecting the previous cultivar’s variability. Plant growth is no exception to this general trend. The biomass decrease was two times higher in CB than CN. Otherwise, this mineral disorder significantly decreased Fe concentration in all plant organs. However, CN accumulated 40% more Fe than CB, resulting from its higher Fe Fe-CR and H-ATPase activities. Our results also demonstrated the close dependence of these metabolic functions on Fe availability in shoots and the strict relationship between Fe-CR and H-ATPase, photosynthesis, and chlorophyll content. Otherwise, CN demonstrated higher efficiency of Fe’s use (FeUE) for the key metabolic functions (photosynthesis, chlorophyll biosynthesis, and plant growth). The relative tolerance of CN as compared to CB was explained by its ability to establish a functional system less vulnerable to iron deficiency that operates effectively under problematic conditions. This system involves metabolic functions in shoots (photosynthesis, chlorophyll biosynthesis, Fe repartition, etc.) and others in roots (H-ATPase, Fe-CR), which are strictly interdependent. Full article

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14 pages, 7681 KiB

Open AccessArticle

Ethylene Regulates Combined Drought and Low Nitrogen Tolerance in Wheat: Proteomic Analysis

by Jiji Yan, Daoping Wang, Shuyu Kang, Zhang He, Xin Li, Wensi Tang, Kai Chen, Yinghong Pan, Yongbin Zhou, Zhaoshi Xu, Jun Chen, Youzhi Ma, Ming Chen and Chunhua Pang

Agronomy 2023, 13(7), 1950; https://doi.org/10.3390/agronomy13071950 - 24 Jul 2023

Cited by 1 | Viewed by 1852

Abstract

Wheat is a staple crop in China’s arid and semi-arid regions. Drought and low nitrogen (LN) are two major constraints to wheat growth and production. However, the molecular mechanism underlying wheat response to both drought and LN stress remains unknown. Accordingly, we conducted [...] Read more.

Wheat is a staple crop in China’s arid and semi-arid regions. Drought and low nitrogen (LN) are two major constraints to wheat growth and production. However, the molecular mechanism underlying wheat response to both drought and LN stress remains unknown. Accordingly, we conducted a proteomic study on the roots of two wheat varieties, Chang6878 (drought tolerant) and Shi4185 (drought sensitive) and compared the differences between drought and combined drought and LN stress treatments. In total, 5143 proteins were identified, of which 163 differentially abundant proteins (DAPs) were uniquely upregulated under drought and LN stress in Chang6878. Enrichment analysis showed that DAPs were mainly involved in mitogen-activated protein kinase signaling, phenylpropanoid biosynthesis, glutathione metabolism, ethylene biosynthesis, ethylene signal transduction, and oxidation–reduction reactions. These DAPs were verified via parallel reaction monitoring and quantitative real-time polymerase chain reaction. Chang6878 was treated with the ethylene synthesis precursor 1-aminocyclopropanecarboxylic acid, and its resistance to drought and LN stress improved. After treatment with the ethylene synthesis inhibitor silver nitrate and ethylene signal transduction inhibitor 1-methylcyclopropene, drought and LN stress resistance reduced. These results provide novel insights into the tolerance mechanisms of Chang6878 to drought and LN stress by altering ethylene synthesis and signal transduction. This study provides a reference for breeding drought- and low-nitrogen-tolerant wheat germplasm resources and a theoretical basis for maintaining food security in arid, barren areas. Full article

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15 pages, 1207 KiB

Open AccessArticle

Physiological Basis of High Nighttime Temperature-Induced Chalkiness Formation during Early Grain-Filling Stage in Rice (Oryza sativa L.)

by Yanli Du, Changzhi Long, Xueyun Deng, Zhengwei Zhang, Jie Liu, Yanghaojun Xu, Dong Liu and Yongjun Zeng

Agronomy 2023, 13(6), 1475; https://doi.org/10.3390/agronomy13061475 - 26 May 2023

Cited by 4 | Viewed by 1673

Abstract

Heat stress during the grain-filling stage seriously affects grain quality in rice. However, very limited information is available regarding the effects of short-term high nighttime temperature (HNT) on grain chalkiness formation in rice. In this paper, the effects of HNT at the early [...] Read more.

Heat stress during the grain-filling stage seriously affects grain quality in rice. However, very limited information is available regarding the effects of short-term high nighttime temperature (HNT) on grain chalkiness formation in rice. In this paper, the effects of HNT at the early grain-filling stage (7 days after ear emergence) on rice chalkiness formation and the potential causes were investigated by using two rice varieties that differed in susceptibility to high temperature. Although the HNT treatment at night dramatically increased the grain chalkiness in Jiuxiangzhan (JXZ) and Huanghuazhan (HHZ), the increase was greater in JXZ compared to HHZ. The net photosynthetic rate and SPAD value were significantly reduced by HNT treatment in the flag leaves of JXZ, while no significant differences were observed in HHZ. Furthermore, HNT treatment reduced the antioxidant enzyme activity in the flag leaves of JXZ, while the opposite was observed in HHZ, exhibiting increased antioxidant enzyme activity. Moreover, HNT treatment altered the endogenous hormone levels, enhanced the enzymatic activities related to starch biosynthesis, and accelerated the filling rate in grains of JXZ when compared to HHZ. Scanning electron microscopy (SEM) observation exhibited that the starch granules in the endosperm of JXZ were loosely packed together and more starch granules with small pits were produced after HNT treatment. Based on these data, we inferred that HNT stress during the early stage of rice grain filling accelerated the grain-filling rate but shortened the grain-filling duration by changing the endogenous hormone levels and enhancing the enzymatic activities responsible for starch biosynthesis, resulting in significant changes in the morphological structure and arrangement of starch granules and eventually causing the occurrence of grain chalkiness. Full article

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18 pages, 19190 KiB

Open AccessArticle

Effect of Branch Bending on the Canopy Characteristics and Growth of Peach (Prunus persica (L.) Batsch)

by Binbin Zhang, Fengshi Zheng, Wenwen Geng, Hao Du, Yuansong Xiao and Futian Peng

Agronomy 2023, 13(4), 1058; https://doi.org/10.3390/agronomy13041058 - 5 Apr 2023

Cited by 4 | Viewed by 2495

Abstract

A reasonable main branch opening angle can improve the canopy light environment of a tree, change the direction of nutrient transport, and promote the formation of flower buds. In this experiment, 3-year-old ‘Lu Hong 618’ was used as the test material to study [...] Read more.

A reasonable main branch opening angle can improve the canopy light environment of a tree, change the direction of nutrient transport, and promote the formation of flower buds. In this experiment, 3-year-old ‘Lu Hong 618’ was used as the test material to study the effects of different main branch opening angles (three treatments: 45°, 65°, and 85°) on the canopy light distribution, canopy characteristics, fruit quality, and flower bud quality of ‘Y’-shaped peach trees. The main findings were as follows: the solar energy utilization in the canopy varied greatly between different main branch opening angles, with the best relative light intensity of the canopy at 85°. In addition, the canopy light distribution on photosynthesis was more reasonable at 85°, and the daily variation range of CO₂ concentration in the inner canopy was the greatest, which facilitated ventilation and light penetration in the inner canopy. With the increase in the main branch opening angle, the new growth of peach trees and the growth of the main branch trunk were inhibited. A reasonable branch opening angle results in good branch structure and leaf morphology. Leaf stomatal morphology and the soluble sugar and starch contents at different levels of the canopy are influenced by canopy light, and higher levels of canopy light can significantly increase the stomatal size and improve the leaf photosynthetic capacity, SPAD value, and soluble sugar and starch contents. With the increase in the main branch opening angle, C/N tended to increase. In addition, the distribution pattern of fruit quality in the canopy was similar to that of light distribution. In the same fruiting part, the fruit quality was higher at 85° and 45° than at 65° and slightly higher at 85° than at 45°, but the difference was not significant. The effects of different main branch opening angle treatments on the fruit weight, flesh firmness, soluble solids, and titratable acid were more significant. The 85° pulling angle effectively increased the light intensity of the different canopy layers of the peach trees and promoted the accumulation of nutrients. An 85° pulling angle can be used as a more suitable pulling angle for peach tree shaping cultivation. Full article

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24 pages, 3229 KiB

Open AccessFeature PaperArticle

Exogenous Application of Indol-3-Acetic Acid and Salicylic Acid Improves Tolerance to Salt Stress in Olive Plantlets (Olea europaea L. Cultivar Picual) in Growth Chamber Environments

by María del Pilar Cordovilla, Carolina Aparicio, Manuel Melendo and Milagros Bueno

Agronomy 2023, 13(3), 647; https://doi.org/10.3390/agronomy13030647 - 23 Feb 2023

Cited by 5 | Viewed by 2290

Abstract

Salinity is one the most recurrent abiotic stresses worldwide and severely affects crop productivity in arid and semiarid environments. This research analyzed several plant growth regulators that could mitigate the effects of salinity on olive plants (Olea europaea L. cultivar Picual). Mist-rooted [...] Read more.

Salinity is one the most recurrent abiotic stresses worldwide and severely affects crop productivity in arid and semiarid environments. This research analyzed several plant growth regulators that could mitigate the effects of salinity on olive plants (Olea europaea L. cultivar Picual). Mist-rooted cuttings were grown in a growth chamber and pretreated with gibberellic acid (GA₃), indole-3-acetic acid (IAA), salicylic acid (SA), and Kinetin by foliar spraying twice a week for three weeks. At the end of the pretreatment, the plants were exposed to 100 mM and 200 mM sodium chloride (NaCl) for six weeks. The results showed that plants pretreated with the plant growth regulators significantly increased their biomass under saline conditions. In addition, IAA and SA restricted the transport of sodium (Na⁺) ions from roots to leaves and improved the leaf potassium (K⁺)/Na⁺ ratio. IAA and SA favored proline, fructose, and mannitol accumulation in leaves at 100 mM and 200 mM NaCl, as did glucose at 200 mM NaCl. Salicylic acid and IAA increased pigments (chlorophylls and carotenoids) and polyamines accumulation under saline conditions. The findings of this study suggest that pretreatments with IAA and SA may be a highly effective way of increasing salt tolerance in olive plantlets. Full article

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2022

Jump to: 2023, 2021

21 pages, 18193 KiB

Open AccessArticle

Heat Stress during Meiosis Has Lasting Impacts on Plant Growth and Reproduction in Wheat (Triticum aestivum L.)

by Mukesh Choudhary, Guijun Yan, Kadambot H. M. Siddique and Wallace A. Cowling

Agronomy 2022, 12(5), 987; https://doi.org/10.3390/agronomy12050987 - 20 Apr 2022

Cited by 9 | Viewed by 3845

Abstract

Meiosis is the least explored stage for thermotolerance in wheat. We evaluated the impact of 5 d of moderate transient daily heat stress during meiosis in the main stem spike on physiological and grain yield traits in 30 diverse wheat cultivars which vary [...] Read more.

Meiosis is the least explored stage for thermotolerance in wheat. We evaluated the impact of 5 d of moderate transient daily heat stress during meiosis in the main stem spike on physiological and grain yield traits in 30 diverse wheat cultivars which vary widely in heat tolerance and sensitivity. We found that a moderate heat stress event during meiosis in the main stem spike had lasting impacts on plant growth and reproduction in heat-sensitive, but not heat-tolerant, wheat cultivars. Heat-tolerant cultivars maintained grain yield, grain number and individual grain weight in the main stem spike and also total plant grain yield and biomass in the heat stress treatment relative to the control. Heat-sensitive cultivars responded to heat stress by producing fewer and smaller grains per spikelet on the main stem, fewer tillers, lower biomass and lower total plant grain yield in the high temperature treatment relative to the control. Heat-sensitive cultivars produced higher flag leaf chlorophyll content in the high temperature treatment relative to the control than heat-tolerant cultivars during the first 3 d of heat treatment. There was small reduction in pollen viability from 98% to 96% following heat stress during meiosis which was unrelated to heat tolerance or sensitivity. Moderate transient heat stress during meiosis did not greatly reduce the production of viable male gametes, but had long-lasting negative impacts on fertilization and subsequent seed production in heat-sensitive cultivars. Full article

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20 pages, 3458 KiB

Open AccessArticle

Rapeseed Morpho-Physio-Biochemical Responses to Drought Stress Induced by PEG-6000

by Maria Batool, Ali Mahmoud El-Badri, Zongkai Wang, Ibrahim A. A. Mohamed, Haiyun Yang, Xueying Ai, Akram Salah, Muhammad Umair Hassan, Rokayya Sami, Jie Kuai, Bo Wang and Guangsheng Zhou

Agronomy 2022, 12(3), 579; https://doi.org/10.3390/agronomy12030579 - 26 Feb 2022

Cited by 35 | Viewed by 5032

Abstract

Rapeseed is a valuable oil crop due to its high nutritious value and ample oil content. The current study provides a comparative analysis of 24 cultivars to better understand the performance and predict the adaptative mechanisms of drought-tolerant and drought-sensitive cultivars based on [...] Read more.

Rapeseed is a valuable oil crop due to its high nutritious value and ample oil content. The current study provides a comparative analysis of 24 cultivars to better understand the performance and predict the adaptative mechanisms of drought-tolerant and drought-sensitive cultivars based on germination and morphophysiological traits during the early seedling stage using PEG-6000 simulated drought conditions. JYZ 158 and FY 520 (tolerant cultivars) and YG 2009 and NZ 1838 (sensitive cultivars) were selected to further explore the role of osmolytes and enzymatic activity in improving drought tolerance. This investigation illustrated that drought stress negatively influenced all studied cultivars; however, the degree of influence was different for each cultivar, suggesting their different potential for drought tolerance. Moreover, enzymatic and osmoregulatory mechanisms were highly efficient in tolerant cultivars compared to sensitive cultivars. Additionally, tolerant cultivars showed higher chlorophyll and lower malondialdehyde (MDA) contents versus sensitive cultivars under drought stress conditions. Higher drought tolerance coincided with higher enzymatic activity and osmolyte content. This work showed that JYZ 158 and FY 520 cultivars had higher drought tolerance, and might be a significant germplasm resource for breeding programs developing drought-tolerant rapeseed. Full article

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13 pages, 2785 KiB

Open AccessArticle

Photosynthesis Alterations in Wheat Plants Induced by Herbicide, Soil Drought or Flooding

by Dessislava Todorova, Vladimir Aleksandrov, Svetoslav Anev and Iskren Sergiev

Agronomy 2022, 12(2), 390; https://doi.org/10.3390/agronomy12020390 - 4 Feb 2022

Cited by 31 | Viewed by 3625

Abstract

The wheat plants were pretreated with the selective herbicide Serrate^® (Syngenta) and subsequently subjected to drought or flooding stress for 7 days. The gas exchange parameters, chlorophyll a fluorescence and leaf pigment content were measured. The measurements were performed during the stress [...] Read more.

The wheat plants were pretreated with the selective herbicide Serrate^® (Syngenta) and subsequently subjected to drought or flooding stress for 7 days. The gas exchange parameters, chlorophyll a fluorescence and leaf pigment content were measured. The measurements were performed during the stress period and after 4 days of plants recovery. Herbicide pretreatment did not cause significant alterations in photosynthesis and fluorescence parameters in alone- or combined-treated seedlings. A significant reduction in gas exchange parameters (net photosynthesis rate, stomatal conductance, transpiration rate, and water use efficiency), F_v/F_m and F_v/F₀ values during drought or flooding was observed. The disruption of photosynthesis together with reduction in the pigment content was stronger in droughted than flooded plants. When the normal irrigation was restored, the gas exchange and fluorescence parameters tended to increase. The comparative analysis of recovery and resilience indices of photosynthetic traits indicate that the plants subjected to drought recovered better than those subjected to flooding stress. Full article

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19 pages, 2624 KiB

Open AccessArticle

Light Intensity: The Role Player in Cucumber Response to Cold Stress

by Tahereh Ashrostaghi, Sasan Aliniaeifard, Aida Shomali, Shiva Azizinia, Jahangir Abbasi Koohpalekani, Moein Moosavi-Nezhad and Nazim S. Gruda

Agronomy 2022, 12(1), 201; https://doi.org/10.3390/agronomy12010201 - 14 Jan 2022

Cited by 29 | Viewed by 4258

Abstract

Low temperatures are a substantial limitation in the geographic distribution of warm-season crops such as cucumber (Cucumis sativus L.). Tolerance to low temperatures varies among different plant species and genotypes when changes in environmental cues occur. Therefore, biochemical and biophysical events should [...] Read more.

Low temperatures are a substantial limitation in the geographic distribution of warm-season crops such as cucumber (Cucumis sativus L.). Tolerance to low temperatures varies among different plant species and genotypes when changes in environmental cues occur. Therefore, biochemical and biophysical events should be coordinated to form a physiological response and cope with low temperatures. We examined how light intensity influences the effects of low temperature on photosynthesis and some biochemical traits. We used chlorophyll fluorescence imaging and polyphasic fluorescence transient to analyze cold stress damage by 4 °C. Photosynthetic Photon Flux Densities (PPFDs) of 0, 300, and 600 μmol m⁻² s⁻¹, in four accessions of cucumber, were investigated. The results show that the negative effects of cold stress are PPFD-dependent. The adverse effect of cold stress on the electron transport chain is more pronounced in plants exposed to 600 μmol m⁻² s⁻¹ than the control and dark-exposed plants, indicated by a disturbance in the electron transport chain and higher energy dissipation. Moreover, biochemical traits, including the H₂O₂ content, ascorbate peroxidase activity, electrolyte leakage, and water-soluble carbohydrate, increased under low temperature by increasing the PPFD. In contrast, chlorophyll and carotenoid contents decreased under low temperature through PPFD elevation. Low temperature induced a H₂O₂ accumulation via suppressing ascorbate peroxidase activity in a PPFD-dependent manner. In conclusion, high PPFDs exacerbate the adverse effects of low temperature on the cucumber seedlings. Full article

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2021

Jump to: 2023, 2022

15 pages, 6106 KiB

Open AccessArticle

Assessing the Adaptive Mechanisms of Two Bread Wheat (Triticum aestivum L.) Genotypes to Salinity Stress

by Ulkar Ibrahimova, Zarifa Suleymanova, Marian Brestic, Alamdar Mammadov, Omar M. Ali, Arafat Abdel Hamed Abdel Latef and Akbar Hossain

Agronomy 2021, 11(10), 1979; https://doi.org/10.3390/agronomy11101979 - 30 Sep 2021

Cited by 7 | Viewed by 2330

Abstract

This work deals with the assessment of physiological and biochemical responses to salt stress, as well as the regulation of the expression of the K⁺/Na⁺ transporter gene-TaHKT1;5 of two Triticum aestivum L. genotypes with contrasting tolerance. According to the [...] Read more.

This work deals with the assessment of physiological and biochemical responses to salt stress, as well as the regulation of the expression of the K⁺/Na⁺ transporter gene-TaHKT1;5 of two Triticum aestivum L. genotypes with contrasting tolerance. According to the observations, salinity stress caused lipid peroxidation; accumulation of soluble sugars and proline; decreased osmotic potential, Fv/Fm value, and K⁺/Na⁺ ratio; and increased the activity of antioxidant enzymes in both genotypes. In the salt-tolerant genotype, the activity of enzymes, the amounts of soluble sugars and proline were higher, the osmotic potential and the lipid peroxidation were lower than in the sensitive one, and the Fv/Fm value remained unchanged. A comparison of the accumulation of Na⁺ and K⁺ ions in the roots and leaves showed that the Na⁺ content in the leaves is lower. The selective transport of K⁺ ions from roots to leaves was more efficient in the salt-tolerant genotype Mirbashir-128; consequently, the K⁺/Na⁺ ratio in the leaves and roots of this genotype was higher compared with the sensitive Fatima genotype. The semi-quantitative RT-PCR expression experiments on TaHKT1;5 indicated that this gene was not expressed in the leaf of the wheat genotypes. Under salt stress, the expression level of the TaHKT1;5 gene increased in the root tissues of the salt-sensitive genotype, while it decreased in the salt-tolerant wheat genotype. The results obtained suggest that the ion status and salt tolerance of the wheat genotypes are related to the TaHKT1;5 gene activity. Full article

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17 pages, 1141 KiB

Open AccessArticle

Evaluation of Traits’ Performance Contributing to Drought Tolerance in Sorghum

by Andekelile Mwamahonje, John Saviour Yaw Eleblu, Kwadwo Ofori, Tileye Feyissa, Santosh Deshpande and Pangirayi Tongoona

Agronomy 2021, 11(9), 1698; https://doi.org/10.3390/agronomy11091698 - 26 Aug 2021

Cited by 5 | Viewed by 3394

Abstract

Sorghum (Sorghum bicolor [L.] Moench) is an important food crop for people in semi-arid Africa. The crop is affected by post-flowering drought; therefore, the study was conducted to screen traits contributing to drought tolerance using BC₂F₄ sorghum genotypes in [...] Read more.

Sorghum (Sorghum bicolor [L.] Moench) is an important food crop for people in semi-arid Africa. The crop is affected by post-flowering drought; therefore, the study was conducted to screen traits contributing to drought tolerance using BC₂F₄ sorghum genotypes in stressed and unstressed water conditions in a split-plot design. Water stress (0 mm/day) was applied at post-flowering to plant maturity in water-stressed treatment. The genotype SE438 produced the highest grain yield (2.65 ton ha⁻¹) in water-stressed environment and NA316C yielded highest (3.42 ton ha⁻¹) under well-watered (7 mm/day) environment. There were significant differences of most traits evaluated at p < 0.01 across environments. The mean squares of traits for genotypes by environments revealed interactions at p < 0.05 and p < 0.01. The indices geometric mean productivity (GMP) and mean productivity (MP) were highly correlated with yield under well-watered (YP) and water-stressed condition (YS) and each other. The first principal axis (PC1) explained 59.1% of the total variation. It is the best indicator of yield potential and drought tolerance of sorghum genotypes in this study. Therefore, further improvement is needed to strengthen drought tolerance and yield in sorghum. Full article

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11 pages, 2538 KiB

Open AccessCommunication

Are Wild Blueberries a Crop with Low Photosynthetic Capacity? Chamber-Size Effects in Measuring Photosynthesis

by Rafa Tasnim and Yong-Jiang Zhang

Agronomy 2021, 11(8), 1572; https://doi.org/10.3390/agronomy11081572 - 6 Aug 2021

Cited by 7 | Viewed by 3410

Abstract

Wild lowbush blueberries, an important fruit crop native to North America, contribute significantly to the economy of Maine, USA, Atlantic Canada, and Quebec. However, its photosynthetic capacity has not been well-quantified, with only a few studies showing its low photosynthetic rates. Its small [...] Read more.

Wild lowbush blueberries, an important fruit crop native to North America, contribute significantly to the economy of Maine, USA, Atlantic Canada, and Quebec. However, its photosynthetic capacity has not been well-quantified, with only a few studies showing its low photosynthetic rates. Its small leaves make accurate leaf-level photosynthetic measurements difficult and introduce potential uncertainties in using large leaf chambers. Here, we determined the photosynthetic rate for five different wild blueberry genotypes using a big leaf chamber enclosing multiple leaves and a small leaf chamber with a single leaf to test whether using big leaf chambers (branch-level measurements) underestimates the photosynthetic capacity. Photosynthetic rates of wild blueberries were significantly (35–47%) lower when using the big leaf chamber, and they are not a crop with low photosynthetic capacity, which can be as high as 16 μmol m⁻² s⁻¹. Additionally, wild blueberry leaves enclosed in the big chamber at different positions of a branch did not differ in chlorophyll content and photosynthetic rate, suggesting that the difference was not caused by variation among leaves but probably due to leaf orientations and self-shading in the big chamber. A significant linear relationship between the photosynthetic rate measured by the small and big leaf chambers suggests that the underestimation in leaf photosynthetic capacity could be corrected. Therefore, chamber-size effects need to be considered in quantifying photosynthetic capacity for small-leaf crops, and our study provided important guidelines for future photosynthesis research. We also established the relationship between the Electron Transport Rate (ETR) and photosynthetic CO₂ assimilation for wild blueberries. ETR provides an alternative to quantify photosynthesis, but the correlation coefficient of the relationship (R² = 0.65) suggests that caution is needed in this case. Full article

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20 pages, 5515 KiB

Open AccessArticle

Silicon Modulates Molecular and Physiological Activities in Lsi1 Transgenic and Wild Lemont Rice Seedlings under Arsenic Stress

by Mohammad Reza Boorboori, Wenxiong Lin, Yanyang Jiao and Changxun Fang

Agronomy 2021, 11(8), 1532; https://doi.org/10.3390/agronomy11081532 - 30 Jul 2021

Cited by 3 | Viewed by 2493

Abstract

Arsenic is one of the most dangerous metalloids, and silicon is a helpful element supporting plants to withstand stress. In this study, three factors were considered, including rice accessions with three different lines, including Lsi1-RNAi line (LE-R), Lsi1 overexpression line (LE-OE), and [...] Read more.

Arsenic is one of the most dangerous metalloids, and silicon is a helpful element supporting plants to withstand stress. In this study, three factors were considered, including rice accessions with three different lines, including Lsi1-RNAi line (LE-R), Lsi1 overexpression line (LE-OE), and their wild type (LE-WT), and silicon and arsenic treatments with two different levels. Analysis of variance in dry weight biomass, protein content, arsenic, and silicon concentration has shown a significant interaction between three factors. Further analysis showed that the silicon concentration of all rice seedlings under silicon treatments increased significantly. The LE-OE line has shown a higher ability to absorb silicon in hydroponic conditions than the wild type, and when the seedlings were exposed to arsenic, the concentration of arsenic in all lines increased significantly. Adding silicon to over-expressed rice lines with the Lsi1 gene creates better arsenic resistance than their wild type. These findings confirmed antagonism between silicon and arsenic, and seedlings exposed to arsenic showed a reduction in silicon concentration in all rice lines. RNA-seq analysis showed 106 differentially expressed genes in the LE-OE line, including 75 up-regulated genes and 31 down-regulated genes. DEGs in the LE-R line were 449 genes, including 190 up-regulated and 259 down-regulated genes. Adding treatment has changed the expression of Calcium-binding EGF domain-containing, Os10g0530500, Os05g0240200 in both LE-OE and LE-R roots. They showed that transgenic cultivars were more resistant to arsenic than wild-type, especially when silicon was added to the culture medium. Full article

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17 pages, 341 KiB

Open AccessReview

Microplastics and Their Effect in Horticultural Crops: Food Safety and Plant Stress

by Gilda Carrasco Silva, Felipe M. Galleguillos Madrid, Diógenes Hernández, Gonzalo Pincheira, Ana Karina Peralta, Miguel Urrestarazu Gavilán, Victor Vergara-Carmona and Fernando Fuentes-Peñailillo

Agronomy 2021, 11(8), 1528; https://doi.org/10.3390/agronomy11081528 - 30 Jul 2021

Cited by 22 | Viewed by 7385

Abstract

The presence of micro and nanoplastics in the food chain constitutes an emergent multifactorial food safety and physiological stress problem, which must be approached with a strategic perspective since it affects public health when consuming products that have this pollutant, such as fish [...] Read more.

The presence of micro and nanoplastics in the food chain constitutes an emergent multifactorial food safety and physiological stress problem, which must be approached with a strategic perspective since it affects public health when consuming products that have this pollutant, such as fish and crustaceans, fruits, and vegetables. In this review, the authors present the results by scientists from different disciplines who are dedicated to discovering their chemical constitution and origin, the contents of these microparticles in edible plants, the contamination of water-irrigated soils, the mechanisms that concentrate microplastics in these soils, methods to determine them, contamination of freshwater sources of cities, and the negative effect of nano and microplastics on various food products and their detrimental impact on the environment. Recent findings of plant uptake mechanisms complement this, but more research is needed. Full article

17 pages, 4065 KiB

Open AccessArticle

Carbohydrate and Amino Acid Dynamics during Grain Growth in Four Temperate Cereals under Well-Watered and Water-Limited Regimes

by Ana María Méndez-Espinoza, Miguel Garriga, Sinda Ben Mariem, David Soba, Iker Aranjuelo and Alejandro del Pozo

Agronomy 2021, 11(8), 1516; https://doi.org/10.3390/agronomy11081516 - 29 Jul 2021

Cited by 4 | Viewed by 2609

Abstract

Grain development in cereals depends on synthesis and remobilisation compounds such as water-soluble carbohydrates (WSCs), amino acids (AAs), minerals and environmental conditions during pre- and post-anthesis. This study analyses the impact of water stress on metabolite (WSCs, AAs and nitrogen) dynamics between the [...] Read more.

Grain development in cereals depends on synthesis and remobilisation compounds such as water-soluble carbohydrates (WSCs), amino acids (AAs), minerals and environmental conditions during pre- and post-anthesis. This study analyses the impact of water stress on metabolite (WSCs, AAs and nitrogen) dynamics between the source (leaves and stems) and sink (grain) organs in triticale, bread wheat, durum wheat and barley. Plants were grown in glasshouse conditions under well-watered (WW) and water-limited (WL) regimes (from flag leaf fully expanded until maturity). The results showed that the stem WSC content and the apparent mobilisation of WSC to the grain were much higher in triticale and were associated with its larger grain size and grain number. In the four cereals, grain weight and the number of kernels per spike were positively associated with stem WSC mobilisation. After anthesis, the AA concentration in leaves was much lower than in the grain. In grain, the main AAs in terms of concentration were Asn, Pro and Gln in triticale, bread, and durum wheat, and Asn, Pro and Val in barley. The water-limited regime reduced grain weight per plant in the four cereal species, but it had no clear effects on WSC content and AAs in leaves and grain. In general, triticale was less affected by WL than the other cereals. Full article

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17 pages, 4570 KiB

Open AccessArticle

Evaluation of the Tolerance Ability of Wheat Genotypes to Drought Stress: Dissection through Culm-Reserves Contribution and Grain Filling Physiology

by Md. Amirul Islam, Rajib Kumar De, Md. Alamgir Hossain, Md. Sabibul Haque, Md. Nesar Uddin, Md. Solaiman Ali Fakir, Md. Abdul Kader, Eldessoky S. Dessoky, Attia O. Attia, Ehab I. El-Hallous and Akbar Hossain

Agronomy 2021, 11(6), 1252; https://doi.org/10.3390/agronomy11061252 - 21 Jun 2021

Cited by 16 | Viewed by 4151

Abstract

Drought stress is one of the limiting factors for grain filling and yield in wheat. The grain filling and determinants of individual grain weight depend on current assimilation and extent of remobilization of culm reserves to grains. A pot experiment was conducted with [...] Read more.

Drought stress is one of the limiting factors for grain filling and yield in wheat. The grain filling and determinants of individual grain weight depend on current assimilation and extent of remobilization of culm reserves to grains. A pot experiment was conducted with eight wheat cultivars at the Pot House to study the grain filling and the contributions of reserves in culm, including the sheath to grain yield under drought stress. Drought stress was enforced by restricting irrigation during the grain-filling period. The plants (tillers) were harvested at anthesis, milk-ripe, and maturity. The changes in dry weights of leaves, culm with sheath, spikes, and grains; and the contribution of culm reserves to grain yield were determined. Results revealed that drought stress considerably decreased the grain filling duration by 15–24% and grain yield by 11–34%. Further, drought-induced early leaf senescence and reduced total dry matter production indicate the minimum contribution of current assimilation to grain yield. The stress reduced the contribution of culm reserves, the water-soluble carbohydrates (WSCs), to the grains. The accumulation of culm WSCs reached peak at milk ripe stage in control, varied from 28.6 to 84 mg culm⁻¹ and that significantly reduced in the range from 14.9 to 40.6 mg culm⁻¹ in stressed plants. The residual culm WSCs in control and stressed plants varied from 1.23 to 8.12 and 1.00 to 3.40 mg g⁻¹ culm dry mass, respectively. BARI Gom 24 exhibited a higher contribution of culm WSCs to grain yield under drought, while the lowest contribution was found in Kanchan. Considering culm reserves WSCs and their remobilization along with other studied traits, BARI Gom 24 showed greater drought tolerance and revealed potential to grow under water deficit conditions in comparison to other cultivars. Full article

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16 pages, 2917 KiB

Open AccessEditor’s ChoiceArticle

Effect of Salinity Stress on Physiological Changes in Winter and Spring Wheat

by Muhammad Sohail Saddiq, Shahid Iqbal, Muhammad Bilal Hafeez, Amir M. H. Ibrahim, Ali Raza, Esha Mehik Fatima, Heer Baloch, Jahanzaib, Pasqualina Woodrow and Loredana Filomena Ciarmiello

Agronomy 2021, 11(6), 1193; https://doi.org/10.3390/agronomy11061193 - 11 Jun 2021

Cited by 130 | Viewed by 12155

Abstract

Salinity is a leading threat to crop growth throughout the world. Salt stress induces altered physiological processes and several inhibitory effects on the growth of cereals, including wheat (Triticum aestivum L.). In this study, we determined the effects of salinity on five [...] Read more.

Salinity is a leading threat to crop growth throughout the world. Salt stress induces altered physiological processes and several inhibitory effects on the growth of cereals, including wheat (Triticum aestivum L.). In this study, we determined the effects of salinity on five spring and five winter wheat genotypes seedlings. We evaluated the salt stress on root and shoot growth attributes, i.e., root length (RL), shoot length (SL), the relative growth rate of root length (RGR-RL), and shoot length (RGR-SL). The ionic content of the leaves was also measured. Physiological traits were also assessed, including stomatal conductance (gs), chlorophyll content index (CCI), and light-adapted leaf chlorophyll fluorescence, i.e., the quantum yield of photosystem II (Fv′/Fm′) and instantaneous chlorophyll fluorescence (Ft). Physiological and growth performance under salt stress (0, 100, and 200 mol/L) were explored at the seedling stage. The analysis showed that spring wheat accumulated low Na+ and high K+ in leaf blades compared with winter wheat. Among the genotypes, Sakha 8, S-24, W4909, and W4910 performed better and had improved physiological attributes (gs, Fv′/Fm′, and Ft) and seedling growth traits (RL, SL, RGR-SL, and RGR-RL), which were strongly linked with proper Na⁺ and K⁺ discrimination in leaves and the CCI in leaves. The identified genotypes could represent valuable resources for genetic improvement programs to provide a greater understanding of plant tolerance to salt stress. Full article

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15 pages, 523 KiB

Open AccessArticle

Defense Responses in the Interactions between Medicinal Plants from Lamiaceae Family and the Two-Spotted Spider Mite Tetranychus urticae Koch (Acari: Tetranychidae)

by Katarzyna Golan, Inmaculada Garrido Jurado, Izabela Kot, Edyta Górska-Drabik, Katarzyna Kmieć, Bożena Łagowska, Barbara Skwaryło-Bednarz, Marek Kopacki and Agnieszka Jamiołkowska

Agronomy 2021, 11(3), 438; https://doi.org/10.3390/agronomy11030438 - 27 Feb 2021

Cited by 7 | Viewed by 3455

Abstract

This study aimed to determine the effects of plant species on the biological parameters of Tetranychus urticae Koch and the time of mite infestation on plant physiology in Ocimum basilicum L., Melissa officinalis L. and Salvia officinalis L. Mite infestation induced various levels [...] Read more.

This study aimed to determine the effects of plant species on the biological parameters of Tetranychus urticae Koch and the time of mite infestation on plant physiology in Ocimum basilicum L., Melissa officinalis L. and Salvia officinalis L. Mite infestation induced various levels of oxidative stress depending on plant species and the duration of infestation. Host plants affected T. urticae life table parameters. The low level of susceptibility was characteristic of S. officinalis, which appeared to be the least infected plant species and reduced mites demographic parameters. Infested leaves of S. officinalis contained elevated levels of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) compared to control. In addition, higher membrane lipid peroxidation and higher activity of guaiacol peroxidase (GPX) and lower activity of catalase (CAT) were recorded with a longer mite infestation. In contrast, O. basilicum appeared to be a suitable host on which T. urticae could develop and increase in number. In basil leaves, increasing levels of hydrogen peroxide and MDA with elevated GPX activity and strongly decreased catalase activity were recorded. Knowledge of the differences in mite susceptibility of the tested medicinal plants described in this study has the potential to be applied in breeding strategies and integrated T. urticae pest management in medicinal plant cultivations. Full article

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13 pages, 2418 KiB

Open AccessArticle

Effects of 24-Epibrassinolide, Bikinin, and Brassinazole on Barley Growth under Salinity Stress Are Genotype- and Dose-Dependent

by Jolanta Groszyk and Magdalena Szechyńska-Hebda

Agronomy 2021, 11(2), 259; https://doi.org/10.3390/agronomy11020259 - 30 Jan 2021

Cited by 10 | Viewed by 3627

Abstract

Brassinosteroids (BRs) are involved in the regulation of many plant developmental processes and stress responses. In the presented study, we found a link between plant growth under salinity stress and sensitivity to 24-epibrassinolide (24-EBL, the most active phytohormone belonging to BRs), brassinazole (Brz) [...] Read more.

Brassinosteroids (BRs) are involved in the regulation of many plant developmental processes and stress responses. In the presented study, we found a link between plant growth under salinity stress and sensitivity to 24-epibrassinolide (24-EBL, the most active phytohormone belonging to BRs), brassinazole (Brz) and bikinin (inhibitors of BR biosynthesis and signaling pathways, respectively). Plant sensitivity to treatment with active substances and salinity stress was genotype-dependent. Cv. Haruna Nijo was more responsive during the lamina joint inclination test, and improved shoot and root growth at lower concentrations of 24-EBL and bikinin under salinity stress, while cv. Golden Promise responded only to treatments of higher concentration. The use of Brz resulted in significant dose-dependent growth inhibition, greater for cv. Haruna Nijo. The results indicated that BR biosynthesis and/or signaling pathways take part in acclimation mechanisms, however, the regulation is complex and depends on internal (genotypic and tissue/organ sensitivity) and external factors (stress). Our results also confirmed that the lamina joint inclination test is a useful tool to define plant sensitivity to BRs, and to BR-dependent salinity stress. The test can be applied to manipulate the growth and stress responses of crops in agricultural practice or to select plants that are sensitive/tolerant to salinity stress in the plant breeding projects. Full article

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33 pages, 1650 KiB

Open AccessEditor’s ChoiceArticle

Consequences and Mitigation Strategies of Abiotic Stresses in Wheat (Triticum aestivum L.) under the Changing Climate

by Akbar Hossain, Milan Skalicky, Marian Brestic, Sagar Maitra, M. Ashraful Alam, M. Abu Syed, Jamil Hossain, Sukamal Sarkar, Saikat Saha, Preetha Bhadra, Tanmoy Shankar, Rajan Bhatt, Apurbo Kumar Chaki, Ayman EL Sabagh and Tofazzal Islam

Agronomy 2021, 11(2), 241; https://doi.org/10.3390/agronomy11020241 - 28 Jan 2021

Cited by 115 | Viewed by 13192

Abstract

Wheat is one of the world’s most commonly consumed cereal grains. During abiotic stresses, the physiological and biochemical alterations in the cells reduce growth and development of plants that ultimately decrease the yield of wheat. Therefore, novel approaches are needed for sustainable wheat [...] Read more.

Wheat is one of the world’s most commonly consumed cereal grains. During abiotic stresses, the physiological and biochemical alterations in the cells reduce growth and development of plants that ultimately decrease the yield of wheat. Therefore, novel approaches are needed for sustainable wheat production under the changing climate to ensure food and nutritional security of the ever-increasing population of the world. There are two ways to alleviate the adverse effects of abiotic stresses in sustainable wheat production. These are (i) development of abiotic stress tolerant wheat cultivars by molecular breeding, speed breeding, genetic engineering, and/or gene editing approaches such as clustered regularly interspaced short palindromic repeats (CRISPR)-Cas toolkit, and (ii) application of improved agronomic, nano-based agricultural technology, and other climate-smart agricultural technologies. The development of stress-tolerant wheat cultivars by mobilizing global biodiversity and using molecular breeding, speed breeding, genetic engineering, and/or gene editing approaches such as CRISPR-Cas toolkit is considered the most promising ways for sustainable wheat production in the changing climate in major wheat-growing regions of the world. This comprehensive review updates the adverse effects of major abiotic stresses and discusses the potentials of some novel approaches such as molecular breeding, biotechnology and genetic-engineering, speed breeding, nanotechnology, and improved agronomic practices for sustainable wheat production in the changing climate. Full article

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