염분에 대한 콩의 생리학적 반응지표 연구

Abstract

The mechanism imparting salt tolerance to crop plants remains still unsolved, although soybean has been classified as a susceptible plant to NaCl. To determine optimum parameters on physiological responses for improving sensitivity of salinity in breeding program, soybean (Glycine max Merr., cv. Gwan-gan) plants were grown in a greenhouse, treated 20 days after emergence for 7 days with NaCl at 0, 30, 60, and 90mM, corresponding to electric conductivity of 1.2, 4.4, 7.3, and 10.4 dS/m, respectively, and assessed 30 days after treatment. Chlorophyll contents were significantly decreased by NaCl () compared to control (1.2 mg/g). Photosynthesis rate by NaCl treatment at at flowering stage was ranged from 5.0 (control) to . Oxygen for respiration was consumed from 5.4 to so that the ratio of (evolution:consumption) was increased with the increase of NaCl, indicating that consumption seems to go beyond evolution. Water potential of leaf at vegetative stage II was ranged from -0.6 to -1.8 MPa and the highest level was observed at mid-day. Water potential by salt stress was decreased with range of compared to control. Transpiration was decreased from 17% to 20% by NaCl stress. Water vapor diffusing resistance of intercellular air space was affected significantly, increasing up to compared to control by NaCl treatment. Salt-treated soybean tended to accumulate , specially in root, with reduced absorption of N, P, , , and contents. Free proline content of soybean leaf as affected by different NaCl concentrations was increased 4.2 times () more than control. NaCl also increased activities of nitrate reductase and peroxidase by and , respectively. The results show that physiological characteristics of soybean plants during assay were useful as the best parameters of salt stress or salt tolerance test to improve sensitivity in screening and breeding program among cultivars or germplasms.