不同水分条件刚毛柽柳开花结实观测

Observation on blossoming and bearing characteristics of Tamarix hispida under different groundwater levels

使用参照对比方法,观测了正常水分条件(参照点)与断流30年后输水河畔不同水分梯度刚毛柽柳(Tamarixhispida)单个花序长、单个花序开花数、单个花序结实量、单个花序结实率和种子发芽率的差别。结果表明:除结实率、发芽率外,参照点与输水河畔不同水分条件刚毛柽柳的各项观测指标均存在极显著差异;应急输水7年后,离河300m,地下水埋深值5.5m左右,刚毛柽柳可保证一定的花序长和开花数;离河500m,地下水埋深值6m左右,刚毛柽柳可保证一定结实量;离河1000m以内,地下水埋深<7.5m,刚毛柽柳种子的结实率和发芽率仍相对较高;干旱条件限制刚毛柽柳的花序长与开花数,随水分条件下降又限制其结实量;在缺水条件下,刚毛柽柳仍保证一定的结实率及发芽率以确保种群的延续。

In this paper, the single inflorescence length, flower number, bearing rate and fruit quantity, and the seed germination rate of Tamarix hispida under different groundwater levels at the riverside in the lower reaches of Tarim River were investigated after the water transportation having been stopped for 30 years, with the normal water condition as the reference. The results showed that all the parameters except single inflorescence bearing rate and seed germination rate had significant differences among the observation points. After 7 years urgent water transporta- tion, the single inflorescence length and flower number were assured at the point 300 m away from the river when the groundwater quantity was assured at the point 500 level was about 5.5 m, and the single inflorescence fruit m away from the fiver when the groundwater level was about 6 m. The single inflorescence bearing rate and seed germination rate were still relatively high at the point 1 000 m away from the river when the groundwater level was less than 7.5 m. Drought condition first restricted the single inflorescence length and flower number, and then, restricted the single inflorescence fruit quantity. Under water deficit, certain rates of inflorescence bearing and seed germination could be still maintained so as to insure the existence of T. hispida population.