scholarly journals Morpho-physiological Changes in Chilli under Drought and Heat Stress

2020 ◽  
pp. 68-77
Author(s):  
V. Rajeswari ◽  
D. Vijayalakshmi ◽  
S. Srinivasan ◽  
R. Swarnapriya ◽  
S. Varanavasiappan ◽  
...  
Keyword(s):  
Heat Stress ◽  
Drought Stress ◽  
Negative Impact ◽  
Yield Reduction ◽  
Optimum Level ◽  
Gas Exchange Parameters ◽  
Physiological Basis ◽  
Randomized Design ◽  
Drought And Heat Stress ◽  
Near Future

Drought spells and heat stress have become quite common and agricultural production would experience a lag in near future. The combined effect of heat and drought stress is expected to cause negative impact on crop growth. Hence, an experiment was framed to assess the morphological and photosynthetic characters of chilli under combined drought and heat stress. Three different genotypes of chilli viz., K1, TNAU chilli hybrid CO 1, Ramanathapuram gundu were subjected to seven drought and temperature treatments. The experiment was designed in factorial completely randomized design (FCRD) at temperature controlled Open Top Chambers (OTC) and drought stress was gravimetically assesed. The results showed that, morphology and photosynthetic characters were affected irrespective of genotypes. The maximum reduction in plant height and leaf area was observed when plants were grown under 40% pot capacity and temperature of + 5°C from the ambient condition. The study also revealed that, the reduction of gas exchange parameters at 40% PC and A + 5°C with yield reduction of almost 76 per cent irrespective of genotypes. Stress treatments reduced the fruit length, fruit diameter compared to control in all genotypes. Stress Tolerence Index was calculated to study the physiological basis under combined drought and heat stress. The optimum level of stress by STI of 0.501 in 60% PC and A+ 3°C was standardized to study the basic physiological functions of chilli.

scholarly journals Assessment of Genetic Diversity for Drought, Heat and Combined Drought and Heat Stress Tolerance in Early Maturing Maize Landraces

Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 518 ◽  
Author(s):  
Nelimor ◽  
Badu-Apraku ◽  
Tetteh ◽  
N’guetta
Keyword(s):  
Climate Change ◽  
Heat Stress ◽  
Drought Stress ◽  
Grain Yield ◽  
Yield Potential ◽  
Yield Reduction ◽  
International Institute ◽  
Improvement Program ◽  
Maize Varieties ◽  
Drought And Heat Stress

Climate change is expected to aggravate the effects of drought, heat and combined drought and heat stresses. An important step in developing ‘climate smart’ maize varieties is to identify germplasm with good levels of tolerance to the abiotic stresses. The primary objective of this study was to identify landraces with combined high yield potential and desirable secondary traits under drought, heat and combined drought and heat stresses. Thirty-three landraces from Burkina Faso (6), Ghana (6) and Togo (21), and three drought-tolerant populations/varieties from the Maize Improvement Program at the International Institute of Tropical Agriculture were evaluated under three conditions, namely managed drought stress, heat stress and combined drought and heat stress, with optimal growing conditions as control, for two years. The phenotypic and genetic correlations between grain yield of the different treatments were very weak, suggesting the presence of independent genetic control of yield to these stresses. However, grain yield under heat and combined drought and heat stresses were highly and positively correlated, indicating that heat-tolerant genotypes would most likely tolerate combined drought and stress. Yield reduction averaged 46% under managed drought stress, 55% under heat stress, and 66% under combined drought and heat stress, which reflected hypo-additive effect of drought and heat stress on grain yield of the maize accessions. Accession GH-3505 was highly tolerant to drought, while GH-4859 and TZm-1353 were tolerant to the three stresses. These landrace accessions can be invaluable sources of genes/alleles for breeding for adaptation of maize to climate change.

scholarly journals HEAT AND DROUGHT STRESS EFFECT IN WHEAT GENOTYPES: A REVIEW

2021 ◽  
Vol 1 (2) ◽  
pp. 77-79
Author(s):  
Sandesh Paudel ◽  
Netra Prasad Pokharel ◽  
Susmita Adhikari ◽  
Sarah Poudel
Keyword(s):  
Heat Stress ◽  
Drought Stress ◽  
Harmful Effect ◽  
Winter Season ◽  
Triticum Aestivum L ◽  
High Yield ◽  
Severe Drought ◽  
Stress Effect ◽  
Cereal Crop ◽  
Drought And Heat Stress

Bread wheat (Triticum aestivum L.) belonging to family Poaceae is the most important cereal crop as it contributes major portion to the world food for the world’s population. Similarly, it is the third most cultivated cereal crop in Nepal in terms of production and area. Wheat is a winter season crop which is usually grown within a temperature range of 15-250C in cold and dry weather. However frequent irrigations are crucial for proper growth of the plant, high yield and high quality of the grain. The annual productivity of wheat has been reported to be 2.49 tons per hectare. Water is found to be one of the most important factors in wheat production and by far not a single water stress tolerant variety has been introduced thus water management is necessary. In Nepal around 35% of the total wheat is cultivated under rainfed condition annually and in Terai this is around 19%. This cultivated area faces a severe drought stress during growing stage and heat stress during anthesis stage. Various studies have suggested that the combined impacts of drought and heat stress had a significant harmful effect on wheat than individual stresses (Stress and Review, 2017). Under drought stress days to anthesis and days to maturity were reduced by 10% and 14% while under heat stress these were reduced by 16% and 20% respectively. Combined effect of drought and heat stress caused reduction in DTA by 25% DTH by and 31%.

scholarly journals Individual and combined effects of transient drought and heat stress on carbon assimilation and seed filling in chickpea

2014 ◽  
Vol 41 (11) ◽  
pp. 1148 ◽  
Author(s):  
Rashmi Awasthi ◽  
Neeru Kaushal ◽  
Vincent Vadez ◽  
Neil C. Turner ◽  
Jens Berger ◽  
...  
Keyword(s):  
Heat Stress ◽  
Drought Stress ◽  
Grain Filling ◽  
Leaf Water Content ◽  
Genotypic Differences ◽  
Combined Effects ◽  
Combined Stress ◽  
Cross Tolerance ◽  
Seed Filling ◽  
Drought And Heat Stress

High temperatures and decreased rainfall are detrimental to yield in chickpea (Cicer arietinum L.), particularly during grain filling. This study aimed to (i) assess the individual and combined effects of drought and heat stress on biochemical seed-filling processes, (ii) determine genotypic differences in heat and drought tolerance, and (iii) determine any cross-tolerance. Plants were grown outdoors in the normal growing season when temperatures during seed filling were <32−20°C or were planted late (temperatures >32−20°C; heat stress). Half of the pots were kept adequately watered throughout, but water was withheld from the others from the initiation of seed filling until the relative leaf water content reached 50% of the irrigated plants (drought stress); all plants were rewatered thereafter until seed maturit. Water was withheld for 13 days (normal sowing) and 7 days (late sowing), so soil moisture decreased by 54–57%. Tests on leaves and seeds were performed after the stress. Individual and combined stress damaged membranes, and decreased cellular oxidising ability, stomatal conductance, PSII function and leaf chlorophyll content; damage was greater under combined stress. Leaf Rubisco activity increased with heat stress, decreased with drought stress and decreased severely with combined stress. Sucrose and starch concentrations decreased in all seeds through reductions in biosynthetic enzymes; reductions were greater under combined stress. These effects were more severe in heat- and drought-sensitive genotypes compared with drought-tolerant genotypes. Drought stress had a greater effect than heat stress on yield and the biochemical seed-filling mechanisms. Drought- and heat-tolerant genotypes showed partial cross-tolerance.

scholarly journals Effects of individual and combined heat and drought stress during seed filling on the oxidative metabolism and yield of chickpea (Cicer arietinum) genotypes differing in heat and drought tolerance

2017 ◽  
Vol 68 (9) ◽  
pp. 823 ◽  
Author(s):  
Rashmi Awasthi ◽  
Pooran Gaur ◽  
Neil C. Turner ◽  
Vincent Vadez ◽  
Kadambot H. M. Siddique ◽  
...  
Keyword(s):  
Heat Stress ◽  
Drought Stress ◽  
Seed Yield ◽  
Oxidative Metabolism ◽  
Combined Stress ◽  
Seed Filling ◽  
Stress Treatment ◽  
Drought Tolerant ◽  
The Individual ◽  
Drought And Heat Stress

Drought and heat stress are two major constraints that limit chickpea (Cicer arietinum L.) yield, particularly during seed filling. The present study aimed (i) to assess the individual and combined effects of drought and heat stress on oxidative metabolism during seed filling, and (ii) to determine any genetic variation in oxidative metabolism among genotypes differing in drought and heat tolerance and sensitivity. The plants were raised in outdoor conditions with two different times of sowing, one in November (normal-sown, temperatures <32°C−20°C (day–night) during seed filling), and the other in February (late-sown, temperatures >32°C−20°C (day–night) during seed filling). Plants were regularly irrigated to prevent any water shortage until the water treatments were applied. At both sowing times, the drought treatment was applied during seed filling (at ~75% podding) by withholding water from half of the pots until the relative leaf water content (RLWC) of leaves on the top three branches reached 42–45%, whereas leaves in the fully irrigated control plants were maintained at RLWC 85–90%. Drought-stressed plants were then rewatered and maintained under fully irrigated conditions until maturity. Several biochemical parameters were measured on the leaves and seeds at the end of the stress treatments, and seed yield and aboveground biomass were measured at maturity. Individual and combined stresses damaged membranes, and decreased PSII function and leaf chlorophyll content, more so under the combined stress treatment. The levels of oxidative molecules (malondialdehyde (MDA) and H2O2) markedly increased compared with the control plants in all stress treatments, especially across genotypes in the combined heat + drought stress treatment (increases in leaves: MDA 5.4–8.4-fold and H2O2 5.1–7.1-fold; in seeds: MDA 1.9–3.3-fold and H2O2 3.8–7.9-fold). The enzymatic and non-enzymatic antioxidants related to oxidative metabolism increased under individual stress treatments but decreased in the combined heat + drought stress treatment. Leaves had higher oxidative damage than seeds, and this likely inhibited their photosynthetic efficiency. Yields were reduced more by drought stress than by heat stress, with the lowest yields in the combined heat + drought stress treatment. Heat- and drought-tolerant genotypes suffered less damage and had higher yields than the heat- and drought-sensitive genotypes under the individual and combined stress treatments, suggesting partial cross-tolerance in these genotypes. A drought-tolerant genotype ICC8950 produced more seed yield under the combined heat + drought stress than other genotypes, and this was associated with low oxidative damage in leaves and seeds.

scholarly journals Amylopectin Chain Length Dynamics and Activity Signatures of Key Carbon Metabolic Enzymes Highlight Early Maturation as Culprit for Yield Reduction of Barley Endosperm Starch after Heat Stress

2019 ◽  
Vol 60 (12) ◽  
pp. 2692-2706 ◽  
Author(s):  
Jose Antonio Cuesta-Seijo ◽  
Alice Jara De Porcellinis ◽  
Angela H�rdum Valente ◽  
Alexander Striebeck ◽  
Cynthia Voss ◽  
...  
Keyword(s):  
Heat Stress ◽  
Heat Wave ◽  
Negative Impact ◽  
Weather Conditions ◽  
Grain Filling ◽  
Yield Reduction ◽  
Hordeum Vulgare L ◽  
Stay Green ◽  
Early Maturation ◽  
Final Yield

Abstract Abiotic environmental stresses have a negative impact on the yield and quality of crops. Understanding these stresses is an essential enabler for mitigating breeding strategies and it becomes more important as the frequency of extreme weather conditions increases due to climate change. This study analyses the response of barley (Hordeum vulgare L.) to a heat wave during grain filling in three distinct stages: the heat wave itself, the return to a normal temperature regime, and the process of maturation and desiccation. The properties and structure of the starch produced were followed throughout the maturational stages. Furthermore, the key enzymes involved in the carbohydrate supply to the grain were monitored. We observed differences in starch structure with well-separated effects because of heat stress and during senescence. Heat stress produced marked effects on sucrolytic enzymes in source and sink tissues. Early cessation of plant development as an indirect consequence of the heat wave was identified as the major contributor to final yield loss from the stress, highlighting the importance for functional stay-green traits for the development of heat-resistant cereals.

Response of growth and nitrogen fixation to pod elimination of three annual Medicago species submitted to drought and subsequent recovery

2016 ◽  
Vol 96 (5) ◽  
pp. 757-764 ◽  
Author(s):  
Hossein Sadeghi ◽  
Farzaneh Fakhari
Keyword(s):  
Nitrogen Fixation ◽  
Drought Stress ◽  
Growth Parameters ◽  
Field Capacity ◽  
Physiological Basis ◽  
Subsequent Recovery ◽  
Randomized Design ◽  
Four Levels ◽  
Annual Medicago ◽  
Medicago Species

This research examined the effect of pod elimination on growth and N2 fixation ability in three annual Medicago species during drought stress and subsequent recovery. This study was carried out as a factorial experiment based on a completely randomized design with four replications. The treatments included annual Medicago species, presence or removal of the pod, and water stress at four levels: 100% (as a control), 80%, 60%, and 40% field capacity (FC) during the period of stress. The results showed that annual Medicago species can be considered as semi-drought tolerant species and their recovery ability from mild and moderate drought stress is relatively good. M. polymorpha performed better and showed higher recovery ability in comparison with other tested species. The results of this study showed that elimination of pods from annual Medicago species before sowing enhanced seedling performance under drought stress. However, the effect of pod elimination showed higher significance on growth parameters than nitrogen fixation. The information from this research would be useful for better understanding the physiological basis of changes in drought resistance, as well as targeted breeding programs, to improve the performance of annual Medicago species under conditions of limited or scarce water supply.

scholarly journals Investigating Combined Drought- and Heat Stress Effects in Wheat under Controlled Conditions by Dynamic Image-Based Phenotyping

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 364
Author(s):  
Lamis Osama Anwar Abdelhakim ◽  
Eva Rosenqvist ◽  
Bernd Wollenweber ◽  
Ioannis Spyroglou ◽  
Carl-Otto Ottosen ◽  
...  
Keyword(s):  
Heat Stress ◽  
Drought Stress ◽  
Infrared Imaging ◽  
Late Phase ◽  
Growth Dynamics ◽  
Crop Productivity ◽  
Heat Sensitivity ◽  
Combined Stress ◽  
Controlled Conditions ◽  
Drought And Heat Stress

As drought and heat stress are major challenges for crop productivity under future climate changes, tolerant cultivars are highly in demand. This study investigated the potential of existing Nordic wheat genotypes to resist unfavorable conditions. Four genotypes were selected based on their heat sensitivity (heat-sensitive: LM19, SF1; heat-tolerant: LM62, NS3). At the tillering stage, the plants were subjected to four treatments under controlled conditions: control, drought, heat and combined drought and heat stress. The morpho-physiological performance was quantified during the early and late phase of stress, as well as the recovery phase. We applied an integrative image-based phenotyping approach monitoring plant growth dynamics by structural Red Green Blue (RGB) imaging, photosynthetic performance by chlorophyll fluorescence imaging and transpiration efficiency by thermal infrared imaging. The results demonstrated that the selected genotypes were moderately affected in their photosynthetic efficiency and growth under drought stress, whereas heat and combined stress caused rapid reductions in photosynthesis and growth. Furthermore, drought stress had a major impact on canopy temperature. The NS3 genotype was the most robust genotype, as indicated by its improved response under all stress treatments due to its relatively small biomass. However, the genotypes showed different tolerance to individual and combined stress.

scholarly journals Physiological Plasticity of Green Gram Stomata to Photosynthesis Traits under Interactive Effects of Elevated CO2, Drought and Heat Stress

2021 ◽  
pp. 109-119
Author(s):  
J. Ranjani Priya ◽  
D. Vijayalakshmi ◽  
A. Vinitha ◽  
M. Raveendran ◽  
V. Babu Rajendra Prasad
Keyword(s):  
Gas Exchange ◽  
Elevated Co2 ◽  
Heat Waves ◽  
Co2 Concentration ◽  
Interactive Effects ◽  
Green Gram ◽  
Combined Stress ◽  
Gas Exchange Parameters ◽  
Randomized Design ◽  
Drought And Heat Stress

Heat waves and droughts are projected to become more widespread as a result of climate change. At the same time, CO2 levels are predicted to have doubled by 2100. The stomatal regulation and gas exchange characteristics were assessed in 25 days old plants of green gram (var Co 8) by exposing them to six different treatments namely, T1: a [CO2] + a T+ irrigation (100%), T2: a [CO2] + a T+ irrigation (50%), T3: a [CO2] + e T (40ºC) + irrigation (100%), T4: e [CO2] – 800 ppm + a T+ irrigation (100%), T5: a [CO2] + combined stress [e T (40ºC) + irrigation (50%) T6: e [CO2] – 800 ppm + combined stress [e T (40ºC) + irrigation (50%)]. The experiment was carried out using Completely Randomized Design (CRD) with three replications. All gas exchange parameters viz., ((photosynthesis rate, stomatal conductance, and transpiration rate) were determined before imposing stress and two weeks after imposing stress. Stomatal characters was examined two weeks after imposing stress. Elevated CO2 stress caused a reduction in stomatal frequency accompanied by larger stomatal size. The study revealed the positive effect of higher CO2 concentration on gas exchange traits of the C3 crops viz., green gram.

scholarly journals Physiological Mechanism of Drought-Resistant Rice Coping with Drought Stress

2020 ◽  
Author(s):  
Benfu Wang ◽  
Xiaolong Yang ◽  
Jianping Cheng ◽  
Liang Chen ◽  
Yuanyuan Jiang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Grain Yield ◽  
Physiological Mechanism ◽  
Photochemical Quenching ◽  
Yield Reduction ◽  
Severe Drought ◽  
Physiological Basis ◽  
Moderate Drought ◽  
Drought Resistant ◽  
Mild Drought

Abstract Drought stress is one of major threats to rice production. The weakening of leaf photosynthesis due to drought is the main reason for the reduction of grain yield, but its mechanism is still obscure. The objectives of this study were to reveal the physiological mechanism of drought stress affecting photosynthetic capacity and grain yield. Pot experiments were conducted with three rice cultivars, Hanyou113 (HY113), Huanghuazhan (HHZ) and Zhonghan3 (ZH3) under four water management treatments (traditional flooding (CK), mild drought stress (LD), moderate drought stress (MD) and severe drought stress (HD)) in 2013 and 2014. Compared with CK, grain yield was significantly reduced by 14.9%, 30.8% and 12.8% in HY113, HHZ and ZH3 under mild drought stress, 32.9%, 33.7% and 22.9% in HY113, HHZ and ZH3 under moderate drought stress and 53.6%, 45.6% and 30.7% in HY113, HHZ and ZH3 under severe drought stress, respectively. The photosynthetic rate (Pn) decreased by 49.0% from 20.0 to 10.2 µmol m-2 s-1 in HY113, and 67.6% from 23.4 to 7.58 µmol m-2 s-1 in HHZ, and 39.3% from 23.4 to 14.2 in ZH3. The Pn of HHZ was similar to that of ZH3 under CK conditions. The yield reduction of drought-resistant cultivars was smaller than that of conventional cultivars. Maintaining leaf water potentia (LWP), Pn, photosystem II (PSII) original light energy conversion efficiency, non–photochemical quenching coefficient (NPQ), and increasing in the ratio of photochemical reaction energy in fluorescence and antioxidant enzyme activity, is the physiological basis to achieve a relatively high photosynthesis. These traits could be the target for breeder to developing drought-tolerant varieties.

scholarly journals Comparative Physiology of Drought and Salinity Stress in Grass Pea (Lathyrus sativus L.) Seedlings

2021 ◽  
pp. 111-119
Author(s):  
P. Chettri ◽  
Kousik Atta ◽  
A. K. Pal
Keyword(s):  
Drought Stress ◽  
Salinity Stress ◽  
Osmotic Potential ◽  
Negative Impact ◽  
Laboratory Research ◽  
Sand Culture ◽  
Grass Pea ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
The Impact

Aims: The aim of this study was to investigate the effect of iso-osmotic potentials of drought and salinity on physiological parameters of grass pea seedlingsas well as to compare varietal responses. Study Design: Completely randomized design. Place and Duration of Study: In the years 2017-2018 and 2018-2019, laboratory research on grass pea varieties BK-14 and Pratik was conducted in the Department of Plant Physiology, Bidhan Chandra Krishi Viswavidyalaya, Nadia, West Bengal, India. Methodology: The effect of iso-osmotic potential of salinity and drought stress was studied using NaCl (50, 100 and 200 mM ) and PEG 6000 (10, 12 and 18%) solutions with -0.2, -0.4, and -0.8 MPa osmotic potential, and the experiment was carried out in sand culture using modified Hoagland solution under diffused light, at about 80±1% relative humidity (R.H.) and a temperature of 22±1oC. Data on different physiological and biochemical parameters were recorded after ten days of seedling growth in sand culture. Statistical analysis was performed on the mean data in all cases following completely randomized design (CRD) by application of INDOSTAT version 7.1 software. Results: The germination of grass pea seeds was more severely affected by drought stress than salinity. Both stresses had a negative impact on most of the parameters studied except for leaf proline and sugar The impact became  more pronounced as the severity of the stress increased. The highest intensity of drought stress was found to be more detrimental to leaf protein and relative water content in BK 14, while Pratik was more drastically affected by the highest level of salinity. Drought was found to have a significant negative impact on leaf starch in both the grass pea varieties. The highest concentration of PEG led to a remarkable increase in leaf proline. Conclusion: The mild to moderate levels (-0.2 and -0.4 MPa)  of stress did not produce much severe effects on the grass pea seedlings, but the highest intensity of stress with an osmotic potential of -0.8 MPa mostly produced drastic effects. There were varietal differences in response to two abiotic stresses. In general, drought stress was found to cause more negative effects on seedling than iso-osmotic potential of salinity stress.

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