Study of the Influence of Abiotic and Biotic Stress Factors on Horticultural Plants

A special issue of Horticulturae (ISSN 2311-7524). This special issue belongs to the section "Biotic and Abiotic Stress".

Deadline for manuscript submissions: closed (31 August 2021) | Viewed by 51132

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Department of Plant Physiology and Biophysics, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland
Interests: plant physiology; plant response to abiotic and biotic stress factors; metal phytotoxicity; enzymatic and non-enzymatic antioxidants; secondary metabolites; photosynthesis
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Guest Editor
Department of Industrial and Environmental Microbiology, Faculty of Biology and Biotechnology, Maria Curie-Sklodowska University in Lublin, Lublin, Poland
Interests: plant biocontrol; bio-fertilization and protection; biotic and abiotic factors of plant resistance; inhibition of phytopathogen growth; soil bioremediation by microorganisms; cell wall-degrading enzymes and microbiological metabolites; siderophores; phytohormones
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Department of Industrial and Environmental Microbiology, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Sklodowska University, Akademicka 19, 20-033 Lublin, Poland
Interests: metal bioavailability; heavy metal bioremediation; metal-induced stress; rhizosphere microorganisms; plant-growth-promoting microorganisms
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

In contrast to their inability to escape from adverse environmental conditions, plants have developed a vast range of adaptations which allow them to cope with unfavorable agents successfully. These stresses are of different nature and are commonly divided into abiotic (physical and chemical factors) and biotic ones. Among abiotic factors are nutrient deficiency, radiation, temperature stress, water stress, salinity, and heavy metal toxicity, which consequently result in oxidative stress. Among the abiotic factors belong pathogens, bacteria, fungi, viruses, insects, and weeds. In the face of stresses, plants can react through a sophisticated defense mechanism classified as innate and acquired or local and systemic responses. These mechanisms are responsible for various morphological, anatomical, biochemical, and physiological implications enabling tolerance or resistance to stressors. Diversification in the attained responses can be the result of the plant species, its age and general condition, as well as the intensity and duration of the stressor. One conclusion remains obvious—in order to survive, plants must generate sufficient strategies to maintain their growth and development.

By being able to better understand the common and distinctive processes taking place in the plant organism and their cross-connections, we will be able to protect plants and apply better solutions to achieve optimal growth parameters. Moreover, such knowledge can be further employed in plant biotechnology to accomplish the desired environmental and industrial goals.

This Special Issue aims to provide deeper insight into the influence of stress factors at the cellular, tissue, organ, and whole plant level in order to extend future applicational features. Both non-modified and genetically modified plants are acceptable. Especially welcome are approaches combining stresses and applications of a wide range of fields, from anatomy, through biochemistry, physiology to molecular biology and genetics.

Prof. Dr. Agnieszka Hanaka
Prof. Dr. Jolanta Jaroszuk-Ściseł
Dr. Małgorzata Majewska
Guest Editors

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Keywords

  • Abiotic stress
  • Biotic stress
  • Oxidative stress
  • Secondary metabolites
  • Phytohormone
  • Signaling pathways
  • Gene expression
  • Photosynthesis
  • Tolerance
  • Resistance

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Published Papers (13 papers)

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Editorial

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6 pages, 210 KiB  
Editorial
Study of the Influence of Abiotic and Biotic Stress Factors on Horticultural Plants
by Agnieszka Hanaka, Małgorzata Majewska and Jolanta Jaroszuk-Ściseł
Horticulturae 2022, 8(1), 6; https://doi.org/10.3390/horticulturae8010006 - 22 Dec 2021
Cited by 5 | Viewed by 3055
Abstract
In changing environmental conditions, horticulture plants are affected by a vast range of abiotic and biotic stresses which directly and indirectly influence plant condition [...] Full article

Research

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13 pages, 2466 KiB  
Article
Effect of Cold Stress on Growth, Physiological Characteristics, and Calvin-Cycle-Related Gene Expression of Grafted Watermelon Seedlings of Different Gourd Rootstocks
by Kaixing Lu, Jiutong Sun, Qiuping Li, Xueqin Li and Songheng Jin
Horticulturae 2021, 7(10), 391; https://doi.org/10.3390/horticulturae7100391 - 11 Oct 2021
Cited by 12 | Viewed by 4331
Abstract
Recently, grafting has been used to improve abiotic stress resistance in crops. Here, using watermelon ‘Zaojia 8424’ (Citrullus lanatus) as scions, three different gourds (Lagenaria siceraria, 0526, 2505, and 1226) as rootstocks, and non-grafted plants as controls (different plants [...] Read more.
Recently, grafting has been used to improve abiotic stress resistance in crops. Here, using watermelon ‘Zaojia 8424’ (Citrullus lanatus) as scions, three different gourds (Lagenaria siceraria, 0526, 2505, and 1226) as rootstocks, and non-grafted plants as controls (different plants were abbreviated as 0526, 2505, 1226, and 8424), the effect of cold stress on various physiological and molecular parameters was investigated. The results demonstrate that the improved cold tolerance of gourd-grafted watermelon was associated with higher chlorophyll and proline content, and lower malondialdehyde (MDA) content, compared to 8424 under cold stress. Furthermore, grafted watermelons accumulated fewer reactive oxygen species (ROS), accompanied by enhanced antioxidant activity and a higher expression of enzymes related to the Calvin cycle. In conclusion, watermelons with 2505 and 0526 rootstocks were more resilient compared to 1226 and 8424. These results confirm that using tolerant rootstocks may be an efficient adaptation strategy for improving abiotic stress tolerance in watermelon. Full article
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17 pages, 1467 KiB  
Article
Exogenous Application of Chitosan Alleviate Salinity Stress in Lettuce (Lactuca sativa L.)
by Geng Zhang, Yuanhua Wang, Kai Wu, Qing Zhang, Yingna Feng, Yu Miao and Zhiming Yan
Horticulturae 2021, 7(10), 342; https://doi.org/10.3390/horticulturae7100342 - 24 Sep 2021
Cited by 31 | Viewed by 4069
Abstract
Soil salinity is one of the major factors that affect plant growth and decrease agricultural productivity worldwide. Chitosan (CTS) has been shown to promote plant growth and increase the abiotic stress tolerance of plants. However, it still remains unknown whether the application of [...] Read more.
Soil salinity is one of the major factors that affect plant growth and decrease agricultural productivity worldwide. Chitosan (CTS) has been shown to promote plant growth and increase the abiotic stress tolerance of plants. However, it still remains unknown whether the application of exogenous CTS can mitigate the deleterious effects of salt stress on lettuce plants. Therefore, the current study investigated the effect of foliar application of exogenous CTS to lettuce plants grown under 100 mM NaCl saline conditions. The results showed that exogenous CTS increased the lettuce total leaf area, shoot fresh weight, and shoot and root dry weight, increased leaf chlorophyll a, proline, and soluble sugar contents, enhanced peroxidase and catalase activities, and alleviated membrane lipid peroxidation, in comparison with untreated plants, in response to salt stress. Furthermore, the application of exogenous CTS increased the accumulation of K+ in lettuce but showed no significant effect on the K+/Na+ ratio, as compared with that of plants treated with NaCl alone. These results suggested that exogenous CTS might mitigate the adverse effects of salt stress on plant growth and biomass by modulating the intracellular ion concentration, controlling osmotic adjustment, and increasing antioxidant enzymatic activity in lettuce leaves. Full article
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10 pages, 15540 KiB  
Communication
Effects of Short-Term Exposure to Low Temperatures on Proline, Pigments, and Phytochemicals Level in Kale (Brassica oleracea var. acephala)
by Valentina Ljubej, Erna Karalija, Branka Salopek-Sondi and Dunja Šamec
Horticulturae 2021, 7(10), 341; https://doi.org/10.3390/horticulturae7100341 - 24 Sep 2021
Cited by 22 | Viewed by 3215
Abstract
Kale (Brassica oleracea var. acephala) is known as a vegetable with good tolerance of environmental stress and numerous beneficial properties for human health, which are attributed to different phytochemicals. In the present study, investigation of how low temperatures affect proline, pigments [...] Read more.
Kale (Brassica oleracea var. acephala) is known as a vegetable with good tolerance of environmental stress and numerous beneficial properties for human health, which are attributed to different phytochemicals. In the present study, investigation of how low temperatures affect proline, pigments and specialized metabolites content was performed using 8-weeks old kale plants subjected to chilling (at 8 °C, for 24 h) followed by short freezing (at −8 °C, for 1 h after previous acclimation at 8 °C, for 23 h). Plants growing at 21 °C served as a control. In both groups of plants (exposed to low temperatures and exposed to short freezing) a significant increase in proline content (14% and 49%, respectively) was recorded. Low temperatures (8 °C) induced an increase of pigments (total chlorophylls 7%) and phytochemicals (phenolic acids 3%; flavonoids 5%; carotenoids 15%; glucosinolates 21%) content, while exposure to freezing showed a different trend dependent upon observed parameter. After freezing, the content of chlorophylls, carotenoids, and total phenolic acids retained similar levels as in control plants and amounted to 14.65 ± 0.36 mg dw g−1, 2.58 ± 0.05 mg dw g−1 and 13.75 ± 0.07 mg dw CEA g−1, respectively. At the freezing temperature, total polyphenol content increased 13% and total flavonoids and glucosinolates content decreased 21% and 54%, respectively. Our results suggest that acclimatization (23 h at 8 °C) of kale plants can be beneficial for the accumulation of pigments and phytochemicals, while freezing temperatures affect differently specialized metabolite synthesis. The study suggests that growing temperature during kale cultivation must be considered as an important parameter for producers that are orientated towards production of crops with an increasing content of health-related compounds. Full article
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19 pages, 3062 KiB  
Article
Influence of Phosphite Supply in the MS Medium on Root Morphological Characteristics, Fresh Biomass and Enzymatic Behavior in Five Genotypes of Potato (Solanum tuberosum L.)
by Richard Dormatey, Chao Sun, Kazim Ali, Tianyuan Qin, Derong Xu, Zhenzhen Bi and Jiangping Bai
Horticulturae 2021, 7(9), 265; https://doi.org/10.3390/horticulturae7090265 - 26 Aug 2021
Cited by 4 | Viewed by 2594
Abstract
Crop production is threatened by low phosphorus (P) availability and weed interference. Obtaining plant genotypes that can utilize Phosphite (Phi) as fertilizer can supplement phosphates (Pi) while providing an environmentally friendly means of weed control. The study was conducted to determine the tolerance [...] Read more.
Crop production is threatened by low phosphorus (P) availability and weed interference. Obtaining plant genotypes that can utilize Phosphite (Phi) as fertilizer can supplement phosphates (Pi) while providing an environmentally friendly means of weed control. The study was conducted to determine the tolerance and enzymatic behavior of five potato genotypes to PO3. Explants were regenerated in vitro from two nodal cuttings and cultured on Murashige and Skoog (MS) medium under controlled conditions for 30 days. Matured plantlets were subcultured for 20 days in MS medium containing (0.25, 0.5 mM) Phi and Pi and No-P (-Phi + -Pi). The results showed significant genotypic variation in tolerance indices among the five genotypes. Atlantic showed greater tolerance to Phi, with highest total root length (50.84%), root projected area (75.09%), root surface area (68.94%), root volume (33.49%) and number of root forks (75.66%). Phi induced an increasing trend in the levels of hydrogen peroxide in the genotypes with the least effect in Atlantic. The comprehensive evaluation analysis confirmed the tolerance of Atlantic genotype with this ranking; Atlantic, Longshu3, Qingshu9, Longshu6 and Gannong2. Antioxidant enzyme activities and proline content also increased significantly under Phi and No-P treatments. The results suggested that potato genotypes with larger root systems may be more tolerant to Phi than genotypes with smaller root systems. Full article
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19 pages, 1581 KiB  
Article
Investigating Evolution and Balance of Grape Sugars and Organic Acids in Some New Pathogen-Resistant White Grapevine Varieties
by Tommaso Frioni, Cecilia Squeri, Filippo Del Zozzo, Paolo Guadagna, Matteo Gatti, Alberto Vercesi and Stefano Poni
Horticulturae 2021, 7(8), 229; https://doi.org/10.3390/horticulturae7080229 - 6 Aug 2021
Cited by 9 | Viewed by 4185
Abstract
Breeding technologies exploiting marker-assisted selection have accelerated the selection of new cross-bred pathogen-resistant grapevine varieties. Several genotypes have been patented and admitted to cultivation; however, while their tolerance to fungal diseases has been the object of several in vitro and field studies, their [...] Read more.
Breeding technologies exploiting marker-assisted selection have accelerated the selection of new cross-bred pathogen-resistant grapevine varieties. Several genotypes have been patented and admitted to cultivation; however, while their tolerance to fungal diseases has been the object of several in vitro and field studies, their productive and fruit composition traits during ripening are still poorly explored, especially in warm sites. In this study, five white pathogen-resistant varieties (PRV) listed as UD 80–100, Soreli, UD 30–080, Sauvignon Rytos, Sauvignon Kretos were tested over two consecutive seasons in a site with a seasonal heat accumulation of about 2000 growing degree days (GDDs), and their performances were compared to two Vitis vinifera L. traditional varieties, Ortrugo and Sauvignon Blanc. Berries were weekly sampled from pre-veraison until harvest to determine total soluble solids (TSS) and titratable acidity (TA) dynamics. All tested PRV exhibited an earlier onset of veraison and a faster sugar accumulation, as compared to Ortrugo and Sauvignon Blanc, especially in 2019. At harvest, Sauvignon Blanc was the cultivar showing the highest titratable acidity (8.8 g/L). Ortrugo and PRV showed very low TA (about 4.7 g/L), with the exception of Sauvignon Rytos (6.5 g/L). However, data disclose that Sauvignon Rytos higher acidity at harvest relies on higher tartrate (+1.1 to +2.2 g/L, as compared to other PRV), whereas in Sauvignon Blanc, high TA at harvest is due to either tartaric (+1 g/L, compared to PRV) and malic (+2.5 g/L, compared to PRV) acid retention. Overall, Sauvignon Rytos is the most suited PRV to be grown in a warm climate, where retaining adequate acidity at harvest is crucial to produce high-quality white wines. Nevertheless, canopy and ripening management strategies must be significantly adjusted, as compared to the standard practice employed for the parental Sauvignon Blanc. Full article
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17 pages, 1300 KiB  
Article
Twenty-Years of Hop Irrigation by Flooding the Inter-Row Did Not Cause a Gradient along the Row in Soil Properties, Plant Elemental Composition and Dry Matter Yield
by Sandra Afonso, Margarida Arrobas and Manuel Ângelo Rodrigues
Horticulturae 2021, 7(7), 194; https://doi.org/10.3390/horticulturae7070194 - 15 Jul 2021
Cited by 5 | Viewed by 2604
Abstract
In hops (Humulus lupulus L.), irrigation by flooding the inter-row can carry away suspended particles and minerals, causing gradients in soil fertility. The effect of more than 20 years of flooding irrigation on soil and plants was evaluated in two hop fields [...] Read more.
In hops (Humulus lupulus L.), irrigation by flooding the inter-row can carry away suspended particles and minerals, causing gradients in soil fertility. The effect of more than 20 years of flooding irrigation on soil and plants was evaluated in two hop fields by measuring soil and plant variables in multiple points along the rows. In a second experiment 1000 kg ha−1 of lime was applied and incorporated into the soil to assess whether liming could moderate any gradient created by the irrigation. At different sampling points along the rows, significant differences were recorded in soil properties, plant elemental composition and dry matter yield, but this was not found to exist over a continuous gradient. The variations in cone yield were over 50% when different sampling points were compared. However, this difference cannot be attributed to the effect of irrigation, but rather to an erratic spatial variation in some of the soil constituents, such as sand, silt and clay. Flooding irrigation and frequent soil tillage resulted in lower porosity and higher soil bulk density in the 0.0–0.10 m soil layer in comparison to the 0.10–0.20 m layer. In turn, porosity and bulk density were respectively positively and negatively associated with crop productivity. Thus, irrigation and soil tillage may have damaged the soil condition but did not create any gradient along the row. The ridge appeared to provide an important pool of nutrients, probably caused by mass flow due to the evaporation from it and a regular supply of irrigation water to the inter-row. Liming raised the soil pH slightly, but had a relevant effect on neither soil nor plants, perhaps because of the small amounts of lime applied. Full article
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20 pages, 5372 KiB  
Article
Signal Intensity of Stem Diameter Variation for the Diagnosis of Drip Irrigation Water Deficit in Grapevine
by Chen Ru, Xiaotao Hu, Wene Wang, Hui Ran, Tianyuan Song and Yinyin Guo
Horticulturae 2021, 7(6), 154; https://doi.org/10.3390/horticulturae7060154 - 15 Jun 2021
Cited by 9 | Viewed by 2865
Abstract
Precise irrigation management of grapevines in greenhouses requires a reliable method to easily quantify and monitor the grapevine water status to enable effective manipulation of the water stress of the plants. This study describes a study on stem diameter variations of grapevine planted [...] Read more.
Precise irrigation management of grapevines in greenhouses requires a reliable method to easily quantify and monitor the grapevine water status to enable effective manipulation of the water stress of the plants. This study describes a study on stem diameter variations of grapevine planted in a greenhouse in the semi-arid area of Northwest China. In order to determine the applicability of signal intensity of stem diameter variation to evaluate the water status of grapevine and soil. The results showed that the relative variation curve of the grapevine stem diameter from the vegetative stage to the fruit expansion stage showed an overall increasing trend. The correlations of MDS (maximum daily shrinkage) and DI (daily increase) with meteorological factors were significant (p < 0.05), and the correlations with SWP, RWC and soil moisture were weak. Although MDS and DI can diagnose grapevine water status in time, SIMDS and SIDI have the advantages of sensitivity and signal intensity compared with other indicators. Compared with MDS and DI, the R2 values of the regression equations of SIMDS and SIDI with SWP and RWC were high, and the correlation reached a very significant level (p < 0.01). Thus, SIMDS and SIDI are more suitable for the diagnosis of grapevine water status. The SIMDS peaked at the fruit expansion stage, reaching 0.957–1.384. The signal-to-noise ratio of SIDI was higher than that of MDS across the three treatments at the vegetative stage. The value and signal-to-noise ratio of SIDI at the flowering stage were similar to those of SIMDS, while the correlation between SIDI and the soil moisture content was higher than that of SIMDS. It can be concluded that that SIDI is suitable as an indicator of water status of grapevine and soil during the vegetative and flowering stages. In addition, the signal-to-noise ratio of SIMDS during the fruit expansion and mature stages was significantly higher than that of SIDI. Therefore, SIMDS is suitable as an indicator of the moisture status of grapevine and soil during the fruit expansion and mature stages. In general, SIMDS and SIDI were very good predictors of the plant water status during the growth stage and their continuous recording offers the promising possibility of their use in automatic irrigation scheduling in grapevine. Full article
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17 pages, 3926 KiB  
Article
Adaptive Morphophysiological Features of Neottia ovata (Orchidaceae) Contributing to Its Natural Colonization on Fly Ash Deposits
by Maria Maleva, Galina Borisova, Nadezhda Chukina, Olga Sinenko, Elena Filimonova, Natalia Lukina and Margarita Glazyrina
Horticulturae 2021, 7(5), 109; https://doi.org/10.3390/horticulturae7050109 - 11 May 2021
Cited by 9 | Viewed by 2820
Abstract
In previous decades, some species of the Orchidaceae family have been found growing in man-made habitats. Neottia ovata is one of the most widespread orchids in Europe, however it is quite rare in Russia and is included in several regional Red Data Books. [...] Read more.
In previous decades, some species of the Orchidaceae family have been found growing in man-made habitats. Neottia ovata is one of the most widespread orchids in Europe, however it is quite rare in Russia and is included in several regional Red Data Books. The purpose of this study was to compare the chemical composition and morphophysiological parameters of N. ovata from two forest communities of the Middle Urals, Russia: natural and transformed (fly ash dump of Verkhnetagil’skaya Thermal Power Station) for determining orchid adaptive features. The content of most of the studied metals in the underground parts (rhizome + roots) of N. ovata was considerably higher than in the leaves, which diminished the harmful effect of toxic metals on the aboveground organs. The adaptive changes in the leaf mesostructure of N. ovata such as an increase in epidermis thickness, the number of chloroplasts in the cell, and the internal assimilating surface were found for the first time. The orchids from the fly ash deposits were characterized by a higher content of chlorophyll b and carotenoids than plants from the natural forest community that evidenced the compensatory response on the decrease in chlorophyll a. The ability of N. ovata from the transformed habitat to maintain a relatively favorable water balance and stable assimilation indexes further contribute to its high viability. The study of orchid adaptive responses to unfavorable factors is necessary for their successful naturalization and introduction into a new environment. Full article
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14 pages, 451 KiB  
Article
Effect of 5-Aminolevulinic Acid (5-ALA) on Leaf Chlorophyll Fast Fluorescence Characteristics and Mineral Element Content of Buxus megistophylla Grown along Urban Roadsides
by Hao Yang, Jianting Zhang, Haiwen Zhang, Yi Xu, Yuyan An and Liangju Wang
Horticulturae 2021, 7(5), 95; https://doi.org/10.3390/horticulturae7050095 - 2 May 2021
Cited by 18 | Viewed by 3019
Abstract
It is well known that trees grown on roadsides suffer from stressful environments, including poor soils, bad weather, and harmful gases from automobile exhaust. Improving the adaptability of roadside trees to adverse environments is important for urban management. An experiment was carried out [...] Read more.
It is well known that trees grown on roadsides suffer from stressful environments, including poor soils, bad weather, and harmful gases from automobile exhaust. Improving the adaptability of roadside trees to adverse environments is important for urban management. An experiment was carried out with six-year-old Buxus megistophylla Levl. hedgerows, where 20 mg/L 5-aminolevulinic acids (5-ALA) solution was sprayed on the blade surface at the end of April. Three months later, plant morphology, chlorophyll fast fluorescence characteristics, antioxidant enzyme activities and the mineral element content were investigated. The results showed that leaf size and thickness were significantly greater with 5-ALA treatment, and the leaf color was also greener than those of the control. 5-ALA treatment significantly promoted the electron transfer activity of the PSII reaction center on the donor side, the reaction center itself and the receptor side. It reduced energy dissipation through the heat with increased photochemical quantum yields. The activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in leaves and roots, were stimulated by 5-ALA treatment. The content of soluble sugars and free proline in leaves was significantly increased by 5-ALA treatment, as were the absorption and accumulation of several kinds of mineral nutrient elements, such as nitrogen, phosphate, calcium, magnesium, iron, copper and boron. Additionally, 5-ALA application significantly increased the content of cadmium, mercury, chromium and lead in the roots but decreased them in the leaves. This implies that 5-ALA may induce a mechanism in B. megistophylla in which toxic elements were intercepted in roots to avoid accumulation in leaves, which ensured healthy growth of the aboveground tissues. 5-ALA may regulate the absorption and utilization of mineral nutrient elements in soil with the interception of toxic heavy metal elements in roots, promote leaf photosynthetic performance, induce the accumulation of soluble sugars and free proline, and improve the antioxidant enzyme systems for plants to adapt to the stressful environment of urban roads. These results provide a basis for 5-ALA applications alongside city roads. Full article
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13 pages, 2620 KiB  
Article
Exogenous EBR Ameliorates Endogenous Hormone Contents in Tomato Species under Low-Temperature Stress
by Parviz Heidari, Mahdi Entazari, Amin Ebrahimi, Mostafa Ahmadizadeh, Alessandro Vannozzi, Fabio Palumbo and Gianni Barcaccia
Horticulturae 2021, 7(4), 84; https://doi.org/10.3390/horticulturae7040084 - 17 Apr 2021
Cited by 41 | Viewed by 4189
Abstract
Low-temperature stress is a type of abiotic stress that limits plant growth and production in both subtropical and tropical climate conditions. In the current study, the effects of 24-epi-brassinolide (EBR) as analogs of brassinosteroids (BRs) were investigated, in terms of hormone content, antioxidant [...] Read more.
Low-temperature stress is a type of abiotic stress that limits plant growth and production in both subtropical and tropical climate conditions. In the current study, the effects of 24-epi-brassinolide (EBR) as analogs of brassinosteroids (BRs) were investigated, in terms of hormone content, antioxidant enzyme activity, and transcription of several cold-responsive genes, under low-temperature stress (9 °C) in two different tomato species (cold-sensitive and cold-tolerant species). Results indicated that the treatment with exogenous EBR increases the content of gibberellic acid (GA3) and indole-3-acetic acid (IAA), whose accumulation is reduced by low temperatures in cold-sensitive species. Furthermore, the combination or contribution of BR and abscisic acid (ABA) as a synergetic interaction was recognized between BR and ABA in response to low temperatures. The content of malondialdehyde (MDA) and proline was significantly increased in both species, in response to low-temperature stress; however, EBR treatment did not affect the MDA and proline content. Moreover, in the present study, the effect of EBR application was different in the tomato species under low-temperature stress, which increased the catalase (CAT) activity in the cold-tolerant species and increased the glutathione peroxidase (GPX) activity in the cold-sensitive species. Furthermore, expression levels of cold-responsive genes were influenced by low-temperature stress and EBR treatment. Overall, our findings revealed that a low temperature causes oxidative stress while EBR treatment may decrease the reactive oxygen species (ROS) damage into increasing antioxidant enzymes, and improve the growth rate of the tomato by affecting auxin and gibberellin content. This study provides insight into the mechanism by which BRs regulate stress-dependent processes in tomatoes, and provides a theoretical basis for promoting cold resistance of the tomato. Full article
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13 pages, 1643 KiB  
Article
The Use of Halophytic Companion Plant (Portulaca oleracea L.) on Some Growth, Fruit, and Biochemical Parameters of Strawberry Plants under Salt Stress
by Sema Karakas, Ibrahim Bolat and Murat Dikilitas
Horticulturae 2021, 7(4), 63; https://doi.org/10.3390/horticulturae7040063 - 26 Mar 2021
Cited by 10 | Viewed by 4216
Abstract
Strawberry is a salt-sensitive plant adversely affected by slightly or moderately saline conditions. The growth, fruit, and biochemical parameters of strawberry plants grown under NaCl (0, 30, 60, and 90 mmol L−1) conditions with or without a halophytic companion plant ( [...] Read more.
Strawberry is a salt-sensitive plant adversely affected by slightly or moderately saline conditions. The growth, fruit, and biochemical parameters of strawberry plants grown under NaCl (0, 30, 60, and 90 mmol L−1) conditions with or without a halophytic companion plant (Portulaca oleracea L.) were elucidated in a pot experiment. Salt stress negatively affected the growth, physiological (stomatal conductance and electrolyte leakage), and biochemical parameters such as chlorophyll contents (chl-a and chl-b); proline, hydrogen peroxide, malondialdehyde, catalase, and peroxidase enzyme activities; total soluble solids; and lycopene and vitamin C contents, as well as the mineral uptake, of strawberry plants. The companionship of P. oleracea increased fresh weight, dry weight, and fruit average weight, as well as the total fruit yield of strawberry plants along with improvements of physiological and biochemical parameters. This study showed that the cultivation of P. oleracea with strawberry plants under salt stress conditions effectively increased strawberry fruit yield and quality. Therefore, we suggest that approaches towards the use of P. oleracea could be an environmentally friendly method that should be commonly practiced where salinity is of great concern. Full article
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Review

Jump to: Editorial, Research

21 pages, 1437 KiB  
Review
Plant Tolerance to Drought Stress in the Presence of Supporting Bacteria and Fungi: An Efficient Strategy in Horticulture
by Agnieszka Hanaka, Ewa Ozimek, Emilia Reszczyńska, Jolanta Jaroszuk-Ściseł and Maria Stolarz
Horticulturae 2021, 7(10), 390; https://doi.org/10.3390/horticulturae7100390 - 11 Oct 2021
Cited by 42 | Viewed by 7928
Abstract
Increasing temperature leads to intensive water evaporation, contributing to global warming and consequently leading to drought stress. These events are likely to trigger modifications in plant physiology and microbial functioning due to the altered availability of nutrients. Plants exposed to drought have developed [...] Read more.
Increasing temperature leads to intensive water evaporation, contributing to global warming and consequently leading to drought stress. These events are likely to trigger modifications in plant physiology and microbial functioning due to the altered availability of nutrients. Plants exposed to drought have developed different strategies to cope with stress by morphological, physiological, anatomical, and biochemical responses. First, visible changes influence plant biomass and consequently limit the yield of crops. The presented review was undertaken to discuss the impact of climate change with respect to drought stress and its impact on the performance of plants inoculated with plant growth-promoting microorganisms (PGPM). The main challenge for optimal performance of horticultural plants is the application of selected, beneficial microorganisms which actively support plants during drought stress. The most frequently described biochemical mechanisms for plant protection against drought by microorganisms are the production of phytohormones, antioxidants and xeroprotectants, and the induction of plant resistance. Rhizospheric or plant surface-colonizing (rhizoplane) and interior (endophytic) bacteria and fungi appear to be a suitable alternative for drought-stress management. Application of various biopreparations containing PGPM seems to provide hope for a relatively cheap, easy to apply and efficient way of alleviating drought stress in plants, with implications in productivity and food condition. Full article
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