Effects of Salinity on Leaf Growth and Photosynthesis in Rice

염처리가 수도잎의 신장 및 광합성능에 미치는 영향

The studies aimed to distinguish between initial (ionic or osmotic) effects of salinisation on growth and the longer-term consequences of excessive salt accumulation. Tall and dwarf varieties of rice were used to provide different growth rates. There was no significant effect upon the day-to-day pattern of growth, upon the ultimate length of leaves that were developing at the time of, or shortly after, salinisation with 50 mM NaCl. Leaves that developed after prolonged exposure of the plants to salinity were shorter. Addition of NaCl, KCl or mannitol to the root medium brought about a cessation of leaf elongation within one minute. Growth at a reduced rate restarted abruptly after a lag period that depended upon the external concentration. Elongation rate recovered to its original value within 24 hours after exposure to 50 mM NaCl, though not at higher concentrations. Addition of NaCl at concentrations up to 100 mM elicited no short-term effect upon photsynthetic gas exchange. No change in turgor pressure was detectable in the growing zone with the resolution of the miniature pressure probe used (about 70 kPa). It is concluded that the initial growth reduction in rice caused by salinisation is due to a limitation of water supply. A clear distinction is made between the initial effects of salt which are recoverable, and the long-term effects which result from the accumulation of salt within expanded leaves.

간장이 다른 수도 2품종에 대하여 NaCl, KCl, Mannitol을 처리하고 잎의 신장과 광합성능의 반응을 조사하였다. 그리고 염처리에 의하여 잎의 신장이 일시적으로 정지하고 신장률이 둔화되는 현상 및 높은 농도에서 광합성능이 저하되는 원인에 대하여 고찰하였다.