多效唑浸种提高稻苗耐旱性

Effect of MET-Soaked Seed on Drought Resistance of Rice Seedlings

应用植物生长调节剂能显著提高作物的耐旱性,从而提高干旱条件下作物的产量(余叔文等 1978,王保民等 1980,Fletcher等 1984,1985)。多效唑(multieffects triazole;MET)是我国80年代生产的一种植物生长延缓剂,其化学名为(2RS,3RS)-1-(4-氯苯基)-4,4-二甲基-2-(1H-1,2,4-三唑-1-基)戊醇-3,它能显著延缓稻苗生长、促进分蘖、防止稻苗移栽后败苗(王熹等 1988a,b)。

MET (Multi-Effects Triazole) is a new plant growth retardant. Rice seeds were soaked in 200 ppm MET solution or water (control) for 48 h, then planted in the same plastic pots and grown in the growth chamber. Water stress was initiated by withholding water supply when the seedlings reached the three-leaf stage. MET pretreatment postponed the wilting of rice seedlings for about 2 days under soil drought and significantly increased the survival rate after rewatering. The treated seedlings resumed growth more rapidly than the control after rewatering. MET pretreatment significantly prevented the decrease of water potential in rice seedlings, but did not prevent the decline of osmotic potential under drought stress. The onset of zero turgor pressure in treated seedlings was about 2 days later than that of control and coincided with the wilting of seedlings. The accumulation of free proline and endogenous ABA was markedly delayed by MET pretreatment. The proline level increased rapidly when the seedlings reached zero turgor pressure, The accumulation of endogenous ABA was about 3 days earlier than in the control plants. The increase of drought resistance of rice seedlings by MET pretreatment was probably due to some modified morphology of seedlings, such as high root/shoot ratio or condensed cell, which improved the water status of shoots.