Leaf gas exchange, chlorophyll fluorescence, growth and root yield of ashwagandha (Withania somnifera Dunal.) under soil moisture stress
2010
Shah, Sonal | Saravanan, R., | Gajbhiye, N.A
Aswagandha (Withania somnifera, Dunal.) is an important medicinal plant. It is cultivated in India as rainfed crop for its roots. A field study was conducted to understand the response of this crop (cv. JA-134) to progressive soil moisture deficit. The treatments imposed were moderate (2 irrigations) and severe stress (single irrigation) along with well watered control (4 irrigations). As the soil moisture stress progressed during the crop growth period, øsoil decreased in stress treatments and reached to -10.93, -1.15 MPa at 169 DAS in severe stress, moderate stress at 30 cm soil depth whereas control had øsoil of -0.0088 MPa. Correspondingly predawn leaf water potentials were -0.615 and -0.506 MPa in severe and moderate stress treatments while, control sustained the øsoil of -0.373 MPa. At 169 DAS, total chlorophyll content was reduced 49% and 60% in moderate and severe stress, whereas proline content increased 2.75 and 3.96 times that of control in moderate and severe stress. Gas exchange and chl-a fluorescence were significantly altered under stress. Moisture stress reduced all the growth parameters studied compared to control plants. Reduction in dry weight of leaves and stems were 19.88% (3.52 g), 36.48% (5.19 g) respectively in severe stress compared to control. Whereas root dry weight increased 35% and 20% respectively in moderate and severe stress compared to control. The increased root biomass partitioning and higher root yield under soil moisture stress helped in off-setting the deleterious effect of water stress.
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