水稻旱地育秧对江南早春低温阴雨逆境的抗性

Resistance of Upland raised Rice Seedlings on Stress of Low Temperature and Overcast Rainy in Early Spring in South of the Changjiang River

３年田间试验资料表明：水稻旱育秧的出苗率和成秧率都比水育秧高；在低温胁迫下，播于旱育苗床的水稻种子存活时间长，具有“土中待晴”的优势；烂秧主要发生在秧苗出土前后和１．１～２．０叶期；受低温胁迫之后出土的秧苗，在一段时间内还会出现死苗现象。在低温期间，旱育秧苗的出叶速度、株高和根系生长都快于水育秧。早粳品种的成秧率明显高于早籼品种。低温累积量，＜１０℃的天数和＜１０℃的雨日是造成烂秧的主要因子。由种子发芽率与低温累积量组成的回归模式，能较精确地模拟成秧率。

Based on the data of the field experiments carried out in three years, the rate of emergence and the growth of rice seedlings on the upland and lowland seedling beds, and their relationships with the associated weather factors were analysed. The results showed that the percentage of emergence and seedling planting percent on the upland were more than that of in the lowland. Under stress of low temperature, seeds life on the upland was longer than that in the lowland. It was because that the seeds in bed wait for climatic change from rain to clear. Two peaks of rotting seedling occurred before or after the sprouts come out of the ground and during the period of 1.1 ￣ 2.0 leaves. If the rice seedling suffered from stress of low temperature before they come out of the ground, the phenomenon of the rotting seedling will still last for a few days. During low temperature, the rates of leaves appearance, growth of stems and root system on the upland were faster than those in the lowland bed. The percentage of rice seedling planting of the early japonica rice is higher than that of the early indica rice. The main factors affecting the rotting seedlings were the accumulated low temperature, <10℃ days and <10℃ rain days. The mathematical models that was made up of germination percentage and accumulated low temperature could accurately simulate the percentage of rice seedling planting.