Morpho-physiological and biochemical traits for heat tolerance in chickpea (Cicer arietinum L.) genotypes
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Date
2016
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CCSHAU
Abstract
The present investigation was carried out with six chickpea genotypes viz. ICCV 92944 (Tolerant,
National check), H 07-120, H 08-75, H 09-90, H 09-96 and HC-1 differing in their heat sensitivity, to study the
high temperature induced changes in morphological, physiological, biochemical, yield and its attributing character
in the field conditions. Sampling was done at 30, 60, 90 and 120 days after sowing (DAS) for growth parameters
and <30 °C (control) and >30 °C (stress) conditions for physiological and biochemical traits. The water potential
(Ψw) and osmotic potential (Ψs) of leaves decreased in all the genotypes in stress (>30 °C) conditions. The water
potential of leaves varied from -0.89 to -1.09 in stress (>30 °C) and from -0.66 to -0.80 in control (<30 °C)
conditions among chickpea genotypes. With exposure to high temperature, RWC (%) of leaves also declined in all
the six genotypes. RWC (%) was higher in H 07-120, followed by ICCV 92944 and lowest in H 09-90 in stress
(>30 °C) conditions. The proline content of leaves increased significantly from 0.766 to 0.821 and 0.659 to 0.737
mg g-1 dry weight in H 07-120 and H 09-90 genotypes,respectively in stress (>30 °C) conditions. Likewise, the
total soluble carbohydrate (TSC) content of leaves also increased from 13.85 to 14.56 and 11.56 to 12.71 mg g-1
dry weight in H 07-120 and H 09-90, respectively. A marked increase in hydrogen peroxide H2O2, lipid
peroxidation (MDA content) and relative stress injury (RSI %) was noticed in leaves which was much higher in H
09-90 than all other six chickpea genotypes in stress (>30 °C) conditions. More negative values of Ψw of leaves, Ψs
of leaves and better accumulation of osmotically active solutes, i.e. proline, TSC in H 07-120, helped in
maintaining the higher RWC % of these organs than noticed in other chickpea genotypes. The specific activities of
ROS scavenging enzymes such as SOD, CAT and POX increased in leaves of all the six chickpea genotypes in
stress (>30 °C) conditions. The increase was more in H 07-120 as compared to other chickpea genotypes. Higher
activities of antioxidant enzymes, lower accumulation H2O2 and MDA content in H 07-120 than all others
indicated that these enzymes play a key role in removal of ROS better in H 07-120 than all other six chickpea
genotypes, thus minimizing the cellular damage caused by ROS in stress (>30 °C) conditions. Pollen viability (%)
was also adversely affected with 4 days exposure to high temperature (>30 °C); the effect being most pronounced
in H 09-90. The yield parameters like number of branches plant-1, number of pods plant-1, number of seeds plant-1,
100 seed weight and seed yield plant-1 were more in H 07-120 than in others chickpea genotypes in late sown
condition. Seed yield had significantly positive correlation with RWC and pollen viability, proline content, total
soluble carbohydrates, CAT, POX, SOD and negative with water potential, osmotic potential, H2O2 and RSI.
Hence, the mechanism of heat tolerance was relatively better in H 07-120 than other six chickpea genotypes as
found from physiological, biochemical, reproductive behavior, yield and its attributing traits.
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