长叶红砂和红砂种子萌发对光照、温度和水分的响应

长叶红砂(Reaumuria trigyna)和红砂(Reaumuria soongorica)均为荒漠地区超旱生小灌木,长叶红砂为红砂属珍稀种,而红砂为广布种。通过种子萌发对光、温和土壤水分需求的研究表明,长叶红砂对光照不敏感,而黑暗有利于红砂的萌发。种子萌发的适宜温度均为恒温20-25℃或15/25℃变温。25℃后,随着温度升高萌发率下降。土壤含水量在3%以上时,有利于两物种的萌发,萌发适宜的含水量都在12%。在各种条件下,珍稀种长叶红砂的萌发均高于广布种红砂,说明种子质量和萌发并没有造成长叶红砂的珍稀濒危。但长叶红砂高萌发率却不利于应对荒漠地区极端和不可预测的环境变化,增加了生存的风险性,可能是其濒危原因之一。

Seed Germination Responses to Light,Temperature and Moisture in Species of Reaumuria trigyna and R. soongorica

Reaumuria trigyna and R.soongorica are xerophytic undershrubs in desert.R.trigyna is a rare species while R.soongorica is a wide species.The studies of the requirement of light,temperature and moisture on seed germination of two species distributed.showed that the seeds of R.trigyna was not sensitive to light,but seeds of R.soongorica had a higher germination rate in dark than in light.The optimal temperature for germination was 20-25℃ or 15/25℃ for both two species.Above 25℃,the higher the temperature was,the lower the germination rate.When sand water content was above 3%,they contributed to germination of two species.The optimal moisture was 12%.The germination of R.trigyna was higher than R.soongorica under different tested conditions indicating that germination features are not the reason responsible for the rare or endangered of R.trigyna.However,the high germination of R.trigyna added survivor risk because that did not handle the changes of extreme and unforecast environment.These could be one reason for rare and endangered of R.trigyna.