Biochemical response trends of Macrotyloma uniflorum, Lam. subjected to dehydration stress in different growth conditions (original) (raw)
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Screening of horse gram (Macrotyloma uniflorum) core collection was carried out under moisture stress conditions in glass house and in poly ethylene glycol 8000 solutions with an osmotic potential of-0.15 MPa to-1.76 MPa after germination. However, selected 50 accessions from the above study were raised under controlled moisture stress conditions to analyze variations in the magnitude of different enzyme activities among the surviving accessions. RWC remained unaltered during moisture stress condition but alteration in the plant structure was observed. Catalase activity and superoxide dismutase increased during moisture stress condition, which varied among the contrasting accessions. However, reduction in polyphenol oxidase and ascorbic acid oxidase activity was observed. The observed difference in anatomy confirms the presence of mechanisms other than antioxidant enzymes. Based on the performance in varying moisture stress conditions, the contrasting D9 and D14 were selected for breeding programme while D13 is recommended as a suitable cultivar under both irrigated and rainfed conditions. Differential enzyme activity, reduction in total sugar production and structural compaction were observed as mechanisms of energy conservation in horse gram to resist moisture stress conditions.
Brazilian Journal of Plant Physiology, 2011
High temperature and salinity are the major ecological factors challenging crop productivity in the arid and semiarid regions of the world. Effects of high temperature (43-45°C) and salt stress (0.6 M) on Macrotyloma uniflorum (Lam.) Verdc. (Horse gram), were evaluated in terms of antioxidants and antioxidant enzymes. Both treatments caused typical stress responses in this tropical leguminosae. Oxidative stress indicators such as H 2 O 2 , TBARS, and proline were significantly elevated. Similarly, the antioxidant enzymes superoxide dismutase (SOD; EC 1.15.1.1), guaiacol peroxidase (POX; EC 1.11.1.7) and acid phosphates (AP; EC 3.1.3.2) were significantly elevated while catalase (CAT; EC 1.11.1.6) was reduced. These treatments had contrasting effects on glutathione reductase (GR; EC1.6.4.2) and b-amylase (EC 3.2.1.1). While temperature stress caused increase in GR and decrease in b-amylase, salt stress caused a counter effect. Contrast was also observed in ascorbate and glutathione which increased in temperature stress and reduced in salt stress. SDS-PAGE analysis indicated entirely different protein profiles in temperature and salt stressed seedlings. Growth rate and fresh mass were affected to same extent, relative to their controls. Taken together these data describes the similarities and peculiarities of key biochemical responses of Horse gram to high temperatures and salinity.
EFFECT OF DROUGHT ON DIFFERENT BIOCHEMICAL PARAMETERS OF PLANT IN VEGETATIVE STAGE
Sustainable Development for Agriculture and Environment, 2018
Agricultural water deficit arises from both insufficient rainfall and soil water during the growing season to sustain a high crop yield. Projections show an increase in intense rain events and at the same time reduction in the number of rain days that leads to increased risk of drought as well as flood. Therefore, under rain fed conditions water scarcity is one of the most widespread limitations to crop production. Tendency of plants to keep up a high potential of water in the tissues under drought is called dehydration avoidance and tolerance that determines plant predisposition to survive from water deficiency is called drought resistance. Drought stress or low water stress has threefold effect on the plant reducing water potential, causing ionic imbalance and disturbing availability of nutrient ions. Terms like physiological unavailability of water or physiological drought are used when the plants become unable to the water from the soil due to its increased osmotic potential, although water may physically be present in sufficient quantities. Such alteration in water status leads to loss of turgor pressure, closure of stomata, significance reductions in transpiration, photosynthesis, protein synthesis and lipid metabolism. The energy requirements are increased due to more utilization in osmo-regulation to save the plants from stress damage.
Antioxidant enzymes activities in Vicia seedlings during drought stress
Ratarstvo i povrtarstvo
Drought greatly affects normal plant growth, endangering physiological and biochemical processes in plants. Under the influence of unfavorable environmental conditions, antioxidant protection systems in plant cell can be activated regardless of the stage of growth and development of plants. The experiment was conducted on three vetches species (V. sativa, V. villosa and V. pannonica) under PEG-induced drought stress. Activity of antioxidant enzymes: superoxide dismutase (SOD, EC 1.15.1.1), ascorbate peroxidase (APx, EC 1.11.1.1) and catalase (CAT, EC 1. 11. 1. 6), was determined in shoots and roots of 10-day-old seedlings. Lack of water during germination period activated all the examined antioxidant enzymes in both organs of all tested Vicia species. The activity of SOD and APx generally increased at higher stress levels, while the enzyme CAT showed different patterns of action in all tested species. The results of this study suggest that drought stress causes the production of oxygen radicals that lead to oxidative stress in plants.
African Journal of Microbiology …, 2012
In drought stress conditions, the imbalance between energy intake and consumption by photosynthetic organ causes the production of reactive oxygen species (ROS) and inability of the plant to control them, which eventually led to stress in the cell membranes and incidence of symptoms caused by oxidative damage. Antioxidant enzymes are considered as the fastest units that fight against reactive oxygen species. In this study, the changes in catalase and peroxidase activities in two levels of drought stress conditions (drought stress and control) and its effect on cell membrane and chlorophyll stability in the tolerant (UnKnown 11, HomaandOhadi), semi-tolerant (Sabalan and Rasad(and sensitive (SARA-PBWYT-85-86-22-5 and SHARK-4-0YC-0YC-0YC-5YC-0YC) lines of wheat were analyzed in a factorial experiment based on randomized complete blocks with three replicates. The drought stress caused increase in the peroxidase enzyme activity of Unknown 11, Ohadi and Rasad lines. Although, no increase in peroxidase enzyme activity was shown, Homa still had the highest rate of enzyme activity in drought and control conditions. The activity of catalase enzyme in stress condition in all investigated lines remained stable or decreased and there was no specific relation between the activity of the enzyme and drought resistant. The highest index of chlorophyll stability in the stress condition was perceived in lines Homa،Ohadi and Unknown 11. Also, the most stabilized and the most inconstant cell membrane in stress condition was related to lines Rasad, Homa and SARA-PBWYT-85-86-22-5. In drought condition, there was a positive correlation between peroxidase enzyme activity, yield and stability of chlorophyll b, whereas we did not perceive any positive correlation between catalase enzyme activity and yield. Moreover, considering the existence of a negative correlation between peroxidase enzyme activity and cell membrane stability, it can be concluded that more activity of peroxidase enzyme in drought stress condition leads to increased cell membrane and chlorophyll stability, and it is related to the drought resistance of different lines.
Plants in nature are continuously exposed to several biotic and abiotic stresses. Among these stresses, drought stress is one of the most adverse factors of plant growth and productivity and considered a severe threat for sustainable crop production in the conditions on changing climate. Drought triggers a wide variety of plant responses, ranging from cellular metabolism to changes in growth rates and crop yields. Understanding the biochemical and molecular responses to drought is essential for a holistic perception of plant resistance mechanisms to water-limited conditions. This review describes some aspects of drought induced changes in morphological, physiological and biochemical changes in plants. Drought stress progressively decreases CO 2 assimilation rates due to reduced stomatal conductance. It reduces leaf size, stems extension and root proliferation, disturbs plant water relations and reduces water-use efficiency. It disrupts photosynthetic pigments and reduces the gas exchange leading to a reduction in plant growth and productivity. The critical roles of osmolyte accumulation under drought stress conditions have been actively researched to understand the tolerance of plants to dehydration. In addition, drought stress-induced generation of active oxygen species is well recognized at the cellular level and is tightly controlled at both the production and consumption levels, through increased antioxidative systems. This review focuses on the ability and strategies of higher plants to respond and adapt to drought stress.
DROUGHT STRESS TOLERANCE AND THE ANTIOXIDANT ENZYME SYSTEM
Acta Biologica Cracoviensia Series Botanica, 2006
We studied the relationship of the antioxidant enzyme system to drought stress tolerance during leaf rolling in the leaf, petiole and root of Ctenanthe setosa (Rosc.) Eichler. Chlorophyll and carotenoid content and the chlorophyll stability index decreased in the early period of drought stress but increased in later periods, approaching the control level as leaf rolling increased. Relative water content decreased, while the root:shoot ratio increased during drought stress. Lipid peroxidation also increased and then declined in the same drought period, contrary to photosynthetic pigment content. Superoxide dismutase (SOD) activity did not significantly change in leaves. In the petiole and root, however, it decreased in the early drought period but increased later. Glutathione reductase (GR) activity did not significantly change in the leaf and petiole versus the control, but increased in root. Peroxidase (POD) activity increased in the leaf and petiole but decreased in the root. A peroxidase isoenzyme activity band present in the control leaves did not appear in leaves exposed to 32 days of drought, but in the later periods that activity increased. Tolerance of drought stress apparently is closely associated with the antioxidant enzyme system as well as leaf rolling in C. setosa.
Drought-induced responses of photosynthesis and antioxidant metabolism in higher plants
Journal of Plant Physiology, 2004
The (Parkia pendula (Willd.) Benth. ex Walp.) species most know as visgueiro is a native specie from the Amazon region, belongs to the family Fabaceae-mimosoideae and has been scientifically studied because it is used in landscape projects and the restoration of degraded areas. Intrinsic responses of this species due to water stress is still very superficial, lacking a larger scientific approach in nitrogen and oxidative parameters. For this, a greenhouse experiment was set up in the Federal Rural University of Amazon with seedlings, where they were submitted to water restriction. The experimental design was completely randomized in a 2 × 3 factorial design (control and water deficit, and three evaluation times), with 5 replications, totaling 30 experimental units. The results showed that the RWC reduced during the experiment from 73.5% to 52.99%, evidencing a lower amount of water in these plants. This condition caused the plants to respond positively to the increase of antioxidant enzymes (catalase, APX and SOD), making the plant defense system efficient. As well as for some variables of nitrogen metabolism. The results showed that the RWC reduced during the experiment from 73.5% to 52.99%, evidencing a lower amount of water in these plants. This condition caused the plants to respond positively to the increase of antioxidant enzymes (catalase, APX and SOD), making the plant defense system efficient. As well as for some variables of nitrogen metabolism. The species in this experimental condition was considered as sensitive to the water stress condition.
Biosciences, Biotechnology Research Asia
Drought poses the most significant environmental constrain that limits the growth and yield efficiency of vegetables around the world. The major challenges lies is to identify potential genetic resources and technology development that improve quality and productivity of vegetable crops under declining land, reducing natural resources and increasing environmental stresses. Varied responses of different crop species/genotypes to water-deficit condition have been studied for a long time, and several morphological, physiological and biochemical characters have been suggested to be responsible for drought tolerance. Understanding the morphological, physiological and biochemical responses to drought is essential for a holistic perception of plant resistance mechanisms to water-limited conditions and also to design screening techniques for drought tolerance that may be employed in crop breeding. Drought stress lead to the overproduction of reactive oxygen species (ROS) in plants which ina...