Morpho-physiological and biochemical traits for cold tolerance of chickpea (Cicer arietinum L.) genotypes
Abstract
The present investigation was carried out with six chickpea genotypes viz. ICCV 88506 (Tolerant,
National check), HC-1, H03-56, H07-120, H08-71 and H09- 96 differing in their cold sensitivity, to study the low
temperature (<5°C) induced changes in morphological, physiological, biochemical, yield and its attributing
character under field conditions. Sampling was done at 30, 60, 90 and 120 days after sowing (DAS) for growth
parameters and 4 day exposure to below (stress) and above (control) 5 °C temperature for physiological and
biochemical parameters. The water potential (Ψw) and osmotic potential (Ψs) of leaves decreased in all the
genotypes after 4 days exposure (DAE) to low temperature (<5 °C). H03-56 showed more negative values Ψw of
leaves i.e. from -0.70 to -0.85 MPa as compared to -0.45 to -0.65 MPa in HC-1, respectively in control (>5 °C) and
stress (<5 °C) conditions. Likewise, the Ψs of leaves decreased from -0.84 to -1.04 MPa in H03-56 and -0.59 MPa
to -0.81 MPa in HC-1. With exposure to low temperature (<5 °C), RWC (%) of leaves also declined in all the six
genotypes. RWC (%) was higher in HC-1, followed by H07-120 and lowest in H03-56 in stress (<5 °C) conditions.
The proline content of leaves increased significantly from 0.781 to 0.913 and 0.605 to 0.798 mg g-1 dry weight,
respectively in HC-1 and H03-56 genotypes in stress (<5°C) conditions. Likewise, the total soluble carbohydrate
(TSC) content of leaves also increased from 18.35 to 22.74 and 16.83 to 19.69 mg g-1 dry weight in HC-1 and
H03-56, respectively. A marked increase in hydrogen peroxide H2O2, lipid peroxidation (MDA content) and
relative stress injury (RSI %) was noticed in leaves which was much highest in H03-56 than all other six chickpea
genotypes in stress (<5 °C) condition. More negative values of Ψw of leaves, Ψs of leaves and better accumulation
of osmotically active solutes, i.e. proline, TSC of HC-1 and H07-120, helped in maintaining the higher RWC % of
these organs than noticed in other genotypes in stress conditions. The specific activities of ROS scavenging
enzymes such as SOD, CAT and POX also increased in leaves of all the six chickpea genotypes, in stress (<5 °C)
condition. The increase was more in HC-1 and H07-120 as compared to other chickpea genotypes. Higher
activities of antioxidant enzymes, lower accumulation H2O2 and MDA content in HC-1 and H07-120 than all
others indicated that these enzymes play a key role in removal of ROS better in these genotypes than all other six
chickpea genotypes, thus minimizing the cellular damage caused by ROS under chilling stress. Pollen viability (%)
was also adversely affected in stress (<5 °C) condition; the effect being most pronounced in H03-56. 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 HC-1 and H07-120 than others in early sown condition.Seed yield had significantly
positive correlation with RWC, pollen viability, proline content, total soluble carbohydrates, SOD, CAT, POX and
negative with water potential, osmotic potential, H2O2 and RSI. Hence, the mechanism of cold tolerance was better
in HC-1 and H07-120 than other six chickpea genotypes as found from physiological, biochemical, reproductive
behavior, yield and its attributing traits studied.
Description
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