水生生物型空心莲子草(Alternanthera philoxeroides)对环境因子的反应及与水稻的竞争

Response of Aquatic Alternanthera philoxeroides to Environmental Factors and Its Competition with Rice

为明确环境因子对水生生物型空心莲子草生活力的影响以及空心莲子草与水稻的竞争关系,采用生物测定方法,分析了低温、干燥、盐碱、水层等因子对空心莲子草茎的活棵率、繁殖茎数和植株生物量的影响,还研究了不同种群密度的空心莲子草对水稻产量性状的影响。空心莲子草茎在4℃低温随后常温处理的活棵率达84%,而在-20℃随后常温处理后完全失去生活力;在含水量为30.2%时,空心莲子草茎的活棵率、繁殖茎数和植株鲜质量比鲜样(含水量93.5%)处理的分别下降了45%、33%和74%;0.1%盐碱水溶液处理就可使空心莲子草茎基本失去生活力;水生生物型空心莲子草茎在土壤湿润和不同水层条件下都能够成活和生长。在水稻100株/m2条件下,接种空心莲子草茎23～360株/m2使水稻减产43%～53%。

To determine the influence of the environmental factors on the viability of aquatic Alternanthera philoxeroides and its competitive ability against rice, the effects of low-temperature, drought stress, salt-alkali and water depth on the survival rate, propagation rate and fresh biomass ofA. philoxeroides plants, and the influence of this weed with different population density on the rice grain yield were studied with bioassay method. The treatment with the stem ofA. philoxeroides treated at 4℃ then grown under normal temperature gaveA, philoxeroides a high viability of 84%, while no viable plants was found at -20℃. Compared with the fresh stem （with water content of 93.5%）, the survival rate, propagated stem number and fresh biomass ofA. philoxeroides stems at water content of 30.2% were reduced by 45%, 33% and 74% respectively. The treatments of the 0. 1 % salt-alkaline solution led to the loss of the viability of A. philoxeroides stem. The A. philoxeroioles stem could grow in wet soil with different water depth. A. philoxeroides with a density of 23--360 plants/m^2 reduced the rice grain yield by 43%--53% when the density of rice plants was 100 plants/m^2.