scholarly journals Cacao (Theobroma cacao L.) Response to Water Stress: Physiological Characterization and Antioxidant Gene Expression Profiling in Commercial Clones

2021 ◽  
Vol 12 ◽  
Author(s):  
Mayra Andreina Osorio Zambrano ◽  
Darwin Alexander Castillo ◽  
Loyla Rodríguez Pérez ◽  
Wilson Terán

The increase in events associated with drought constraints plant growth and crop performance. Cacao (Theobroma cacao L.) is sensitive to water deficit stress (DS), which limits productivity. The aim of this research was to characterise the response of seven (CCN51, FEAR5, ICS1, ICS60, ICS95, EET8, and TSH565) commercially important cacao clones to severe and temporal water deficit stress. Ten-month-old cacao trees were submitted to two treatments: well-watered and water-stressed until the leaf water potential (Ψleaf) reached values between −3.0 and −3.5 MPa. The effects of hydric stress on water relations, gas exchange, photochemical activity, membrane integrity and oxidative stress-related gene expression were evaluated. All clones showed decreases in Ψleaf, but TSH565 had a higher capacity to maintain water homeostasis in leaves. An initial response phase consisted of stomatal closure, a general mechanism to limit water loss: as a consequence, the photosynthetic rate dropped by approximately 98% on average. In some clones, the photosynthetic rate reached negative values at the maximum stress level, evidencing photorespiration and was confirmed by increased intracellular CO2. A second and photosynthetically limited phase was characterized by a drop in PSII quantum efficiency, which affected all clones. On average, all clones were able to recover after 4 days of rewatering. Water deficit triggered oxidative stress at the early phase, as evidenced by the upregulation of oxidative stress markers and genes encoding ROS scavenging enzymes. The effects of water deficit stress on energy metabolism were deduced given the upregulation of fermentative enzyme-coding genes. Altogether, our results suggest that the EET8 clone was the highest performing under water deficit while the ICS-60 clone was more susceptible to water stress. Importantly, the activation of the antioxidant system and PSII repair mechanism seem to play key roles in the observed differences in tolerance to water deficit stress among clones.

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1404
Author(s):  
Muhammad Nawaz ◽  
Xiukang Wang ◽  
Muhammad Hamzah Saleem ◽  
Muhammad Hafeez Ullah Khan ◽  
Javaria Afzal ◽  
...  

Use of Plantago ovata Forsk leaf (also known as blond plantain or isabgol) extract is a novel approach for ameliorating water stress in various agronomic crops such as maize (Zea mays L.). To examine the potential roles of P. ovata extract (0, 20 and 40%) in increasing seed germination, plant growth, photosynthetic measurements, stomatal properties, oxidative stress and antioxidant response, ions uptake and the relationship between studied parameters, we investigated the impacts of its short-term seed priming on Z. mays L. elite cultivar “Cimmyt-Pak” under a control environment and a water deficit stress environment (induced by PEG). It was evident that water deficit stress conditions induced a negative impact on plant growth, stomatal properties and ion uptake in different organs of Z. mays. The decrease in growth-related attributes might be due to overproduction of oxidative stress biomarkers, i.e., malondialdehyde (MDA) contents, hydrogen peroxide (H2O2) initiation, and electrolyte leakage (%), which was also overcome by the enzymatic antioxidants, i.e., superoxidase dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) and non-enzymatic antioxidants, which increased under the water stress environment. However, seed priming with P. ovata extract positively increased germination rate and growth profile, and protected photosynthetic apparatus and stomatal properties by decreasing oxidative stress indicators and increasing activities of antioxidant compounds. Our results also depicted that the optimum concentration of P. ovata extract for Z. mays seedlings under water stress conditions was 20%, while a further increase in P. ovata extract (40%) induced a non-significant negative impact on growth and biomass of Z. mays seedling. In addition, the effect was more promising on Z. mays seedlings when grown under controlled conditions. Here, we concluded that the understanding of the role of seed priming with P. ovata extract in the increment of growth-related attributes, photosynthetic apparatus (Pn, Gs, Ts and Ci) and nutrient uptake (Ca2+, Fe2+, P and Mg2+) introduces new possibilities for their effective use in water deficit stress environments and shows a promising foundation for Z. mays tolerance against water deficit stress conditions.


2008 ◽  
Vol 28 (3) ◽  
pp. 125-134 ◽  
Author(s):  
Guidong Yue ◽  
Yunlong Zhuang ◽  
Zhaoxia Li ◽  
Li Sun ◽  
Juren Zhang

The whole-genomic gene-expression changes of maize (Zea mays L.) plants in response to water-deficit stress at the heading stage have not been previously studied. The present work utilized a maize oligonucleotide array (‘57K’, ~57000 sequences; http://www.maizearray.org/) representing more than 30000 unique genes, to profile transcriptome changes in maize leaves subjected to 1d (day) and 7d water-deficit stress. After 1d and 7d water-stress treatment, 195 and 1008 differential genes were identified respectively. One-third of 1d-water-stress-induced genes had known or putative functions in various cellular signalling pathways, indicating that signal-transduction-related genes play important roles in the early responses of maize leaves to water stress. The 7d-stress-regulated genes were involved in a broad range of cellular and biochemical activities. The most notable genes may function in compatible osmolyte metabolism, particularly in proline, sucrose, trehalose and raffinose metabolism in the leaves. The present study provided a valuable starting point for further elucidation of molecular mechanisms in the drought tolerance of maize plants.


2021 ◽  
Vol 66 (1) ◽  
pp. 80-86
Author(s):  
Thin Pham Thi Thanh ◽  
Bang Cao Phi ◽  
Hai Nguyen Thi Thanh ◽  
Khuynh Bui The ◽  
Mai Nguyen Phuong ◽  
...  

Indian Lettuce (Lactuca indica L.) is a valuable medicinal herb but there are still no many researches about this plant. In this work, the physiological responses of Indian lettuce plants under water deficit conditions (5, 8, and 11 days of water stress) were investigated. The Indian lettuce wilted after 5 days of water stress (66.66%), the wilting rate increased after 8 (93.33%) and 11 days (100%) of water stress. The longer duration of water deficit stress caused the slower recovery of plants after rewatering. The water deficit stress caused a decrease in chlorophyll fluorescence, non-associated water content as well as flower formation of Indian lettuce. But the water deficit stress increases the associated water content and the flowering time of this plant.


1988 ◽  
Vol 28 (3) ◽  
pp. 321 ◽  
Author(s):  
SJ Blaikie ◽  
FM Martin ◽  
WK Mason ◽  
DJ Connor

Field canopy chambers were used to measure the effect of a range of soil water contents from surface ponding to very dry soil and the effect of high summer temperatures on the photosynthesis of irrigated white clover and paspalum pastures. Water was ponded for 5-12 days on swards of white clover and paspalum at full cover and on others that had been defoliated to a height of 50 mm. Photosynthetic rate was monitored each day and compared with a non-ponded control. In all cases there was little response in photosynthetic rate to ponding either with or without supplemental nitrogen fertiliser. Photosynthesis of full swards of white clover and paspalum was monitored during a drying cycle following irrigation and compared with the photosynthesis of a well-watered control. Soil water deficit was expressed in terms of cumulative evaporation minus rainfall (mm E - R) after irrigation. Water deficit stress reduced the maximum photosynthetic rate of white clover by 50% (from 0.8 mg CO2/m2.s at 25 mm E - R to 0.4 mg CO2/m2.s at 75 mm E - R), but the photosynthetic rate of paspalum did not decline until 70 mm E - R. At high irradiance, temperatures between 24 and 33�C had little effect on the photosynthetic rate of well-watered white clover, whereas the rate in paspalum was higher at temperatures between 29 and 38�C than at temperatures of 24-29�C. The slow surface drainage and subsequent rapid drying of the root-zone of flood irrigated soils, combined with the high temperatures experienced in northern Victoria during summer, favour paspalum and severely limit the productivity of white clover.


2012 ◽  
Vol 4 (1) ◽  
pp. 112-115 ◽  
Author(s):  
Hossein MARDANI ◽  
Hassan BAYAT ◽  
Amir Hossein SAEIDNEJAD ◽  
Ehsan Eyshi REZAIE

Impacts of various concentrations of salicylic acid (SA) on cucumber (Cucumis sativus L.) seedling characteristic were evaluated under different water stress levels by using a factorial arrangement based on completely randomized design with three replications at experimental greenhouse of Ferdowsi University of Mashhad, Iran. The studied factors included three water deficit levels (100% FC, 80% FC, and 60% FC) considered as first factor and five levels of SA concentrations (0, 0.25, 0.5, 0.75, and 1 mM) as second factor. Results showed that foliar application of SA at the highest concentration enhanced leaf area, leaf and dry weight while decreased stomatal conductance under high level of water deficit stress. Though, severe water deficit stress sharply raised the SPAD reading values. In general, exogenous SA application could develop cucumber seedling characteristic and improve water stress tolerance.


2016 ◽  
Vol 37 (2) ◽  
Author(s):  
Sarang S. Sapre ◽  
Dinesh N. Vakharia

Silicon’s role in mediating resistance against various stresses has been a matter of focus in the past decade. Poaeceae family plants are known as high accumulators of silicon. Wheat shows rapid absorption, the optimum accumulation of silicon occurring at around 20 days. Silicon plays a role as a mechanical and a physiological barrier. It also alters the levels of osmolytes and antioxidant enzymes which are a first line of defense in the water deficit stress; also reducing the levels of oxidative stress factors such as hydrogen peroxide. But the results vary with respect to the modes of stress application and its duration. Nowadays, foliar mode of silicon application is carried out compared to the traditional soil application yielding some promising results. Further studies are needed to confirm the mechanisms governing protection which can be done with the comparison of the transcriptome analysis of the stressed plants and also microscopic studies revealing the site of deposition.


2018 ◽  
Vol 69 (6) ◽  
pp. 594 ◽  
Author(s):  
Goudarz Ahmadvand ◽  
Somayeh Hajinia

Piriformospora indica is one of the cultivable root-colonising endophytic fungi of the order Sebacinales, which efficiently promote plant growth, uptake of nutrients, and resistance to biotic and abiotic stresses. The aim of this study was to evaluate the effect of P. indica on millet (Panicum miliaceum L.) under water-stress conditions. Two field experiments were carried out in a factorial arrangement at Bu-Ali Sina University of Hamedan, Iran, during 2014 and 2015. The first factor was three levels of water-deficit stress, with irrigation after 60 mm (well-watered), 90 mm (mild stress) and 120 mm (severe stress) evaporation from pan class A. The second factor was two levels of fungus P. indica: inoculated and uninoculated. Results showed that water-deficit stress significantly decreased grain yield and yield components. Colonisation by P. indica significantly increased number of panicles per plant, number of grains per panicle and 1000-grain weight, regardless of water supply. Inoculation with P. indica increased grain yield by 11.4% (year 1) and 19.72% (year 2) in well-watered conditions and by 35.34% (year 1) and 32.59% (year 2) under drought stress, compared with uninoculated plants. Maximum flag-leaf area (21.71 cm2) was achieved with well-watered conditions. Severe water stress decreased flag-leaf area by 53.36%. Flag-leaf area was increased by 18.64% by fungus inoculation compared with the uninoculated control. Under drought conditions, inoculation with P. indica increased plant height by 27.07% and panicle length by 9.61%. Severe water stress caused a significant decrease in grain phosphorus concentration, by 42.42%, compared with the well-watered treatment. By contrast, grain nitrogen and protein contents were increased about 30.23% and 30.18%, respectively, with severe water stress. Inoculation with P. indica increased grain phosphorus by 24.22%, nitrogen by 7.47% and protein content by 7.54% compared with control. Water stress reduced leaf chlorophyll and carotenoid concentrations, whereas P. indica inoculation enhanced chlorophyll concentrations by 27.18% under severe water stress. The results indicated the positive effect of P. indica on yield and physiological traits of millet in both well-watered and water-stressed conditions.


2011 ◽  
Vol 39 (2) ◽  
pp. 153 ◽  
Author(s):  
Nourali SAJEDI ◽  
Hamid MADANI ◽  
Ahmad NADERI

This study was carried out to investigate effects of microelements under water deficit stress at different growth stages on antioxidant enzyme alteration, chemical biomarker and grain yield of maize in the years 2007 and 2008. The experiment was conducted in a split plot factorial based on a randomized complete block design with four replications. There were three factors, water deficit stress at different stages of growth as main plot and combinations of selenium (with and without using) and microelements (with and without using) as sub plots. The result indicated that the activity of superoxide dismutase and malondialdehyde content under water deficit stress increased, but grain yield was reduced. The highest grain yield was obtained from optimum irrigation, while in the case of with water deficit stress at V8 stage it was non significant. Selenium spray increased activity of superoxide dismutase enzyme, malondialdehyde content of leaves in V8, R2 and R4 stages and also grain yield. Application of microelements increased the leaves superoxide dismutase enzyme activity and malondialdehyde content. Selenium and microelements spray under water deficit stress conditions during vegetative growth and dough stage increased grain yield in comparison to not spraying elements under water stress conditions. The present results also showed that by using selenium and microelements under water stress can obtain acceptable yield compared to not using these elements.


2014 ◽  
Vol 71 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Hanna Bandurska ◽  
Jolanta Floryszak-Wieczorek

The purpose of this paper was to examine the effect of water deficit on membrane injuries, superoxide radical generation and lipid peroxidation in the leaves of two barley genotypes. Six-day-old seedlings of the cv. Aramir and line R567 were used in the experiments. According to our earlier work these genotypes significantly differ in the level of membrane injuries under water deficit conditions. Water stress was applied directly to leaves or to roots. The stress caused considerable membrane injuries in the leaves of all genotypes investigated.The percentage membrane injury was higher in the line R567 than in the cv. Aramir. Water stress imposed on leaves caused higher membrane injuries than water stress imposed on roots. The water stress treatment followed by an oxidative stress in the leaves. Line R567 having noticeably larger membrane injuries also exhibited a higher level of superoxide radical generation than the cv. Aramir. The level of lipid peroxidation increased in the both genotypes under the conditions of water stress imposed on leaves, but not on roots.


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