INVESTIGATION OF DROUGHT STRESS IN PEPINO (SOLANUM MURICATUM AIT. CV. MISKI) LEAVES

摘要

The effect of potassium (K) and calcium (Ca) on growth and antioxidant defence system of salt-stressed Indian mustardplants was studied. Twenty-day-old Indian mustard plants grown hydroponically in Hoagland’s growth medium wererandomly divided into five groups. T0 served as control and did not receive any additional K or Ca (except that present inHoagland solution), T1 received 150 mM NaCl, T2 was given an additional doze of 6 mM K, T3 was given 5.6 mM Ca asadditional doze, while as T4 received a combination of 150 mM NaCl + 6 mM K + 5.6 mM Ca. The response of the plantswas studied ten days after treatment. Salt stress inhibited growth parameters including biomass, chlorophyll content, proteincontent and NR activity. Membrane damage was induced by the salt treatment with a concurrent increase in antioxidantdefence system and proline content. Individual application of K and Ca mitigated the negative influence of the stress withthe maximum alleviating potential exhibited by the combined application of these nutrients. Results obtained on real timeexpression of genes encoding enzymatic antioxidants (SOD, APX, CAT and GR), NR and proline supported our findingswith biochemical assays. We conclude from the study that maintaining high K and Ca levels may serve as an effectivemeans for regulating the growth and productivity of Indian mustard plants under saline conditions.