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以油松(Pinus tabuliformis)、侧柏(Platycladus orientalis)、元宝枫(Acer truncatum)和刺槐(Robinia pseudoacacia)幼树为研究对象,采用改良冲洗法测定不同分枝级和茎段所在区域的水力结构参数,研究CO_2浓度升高对4个树种水力结构及水分运输安全性和有效性的影响。结果表明:CO_2浓度升高,4个树种在3个分枝级(0、1和2级分枝)的比导率(Ks)和叶比导率(LSC)增加,而侧柏和刺槐在3个分枝的导水率损失(PLC)均下降,油松2级和元宝枫0和1级分枝的PLC下降,其中2级分枝的参数变化最为显著,侧柏、油松和刺槐2级分枝的Ks升高了12.8%、19.6%和51.24%,PLC下降了11.80%、9.6%和51.01%,而元宝枫2级分枝的Ks和PLC均升高。CO_2浓度升高对油松和侧柏非限速区的导水率(Kh)的提高大于限速区,元宝枫和刺槐则相反,而PLC不受CO_2浓度升高的影响。高CO_2浓度对侧柏和元宝枫提高非限速区Ks和LSC大于限速区,油松和刺槐则相反。4个树种在不同分枝级采取不同的方式来适应CO_2浓度的升高,采取的生态策略包括:保持较高的水分运输有效性,同时提高有效性和安全性,和减轻安全性而对有效性的折衷;而在不同茎段所在区域采取保持较高的水分运输效率来适应大气CO_2浓度的升高。
The hydraulic structures of Pinus tabuliformis, Platycladus orientalis, Acer truncatum and Robinia pseudoacacia were studied by improved flushing method Parameters, to study the effects of CO 2 concentration on the hydraulic structure and water transport safety and availability of four tree species. The results showed that the specific conductivity (Ks) and leaf specific conductance (LSC) of four tree species increased in three branches (0, 1 and 2 branches) The water cut loss (PLC) of 3 branches decreased, while the PLC of Pinus tabulaeformis 2 and 0 and 1 branches decreased. The parameters of 2 branches changed most significantly, The Ks of the second grade branches increased by 12.8%, 19.6% and 51.24%, while the PLCs decreased by 11.80%, 9.6% and 51.01%, while the Ks and PLCs increased. The increase of CO 2 concentration on the hydraulic conductivity (Kh) of Pinus tabulaeformis and Platycladus orientalis non-restriction zone was more than that of the speed restriction zone, while that of A. bungeana and R. pseudoacacia was opposite, while PLC was not affected by the increase of CO 2 concentration. The high CO_2 concentration increased the Ks and LSC in the non-speed limit zone and the speed limit zone in the oriental arborvitae and the locust tree, but the opposite occurred in the pine and the locust tree. The four tree species adopted different ways to adapt to the increase of CO 2 concentration at different branch levels. The ecological strategies taken include: to maintain high efficiency of water transport, at the same time to improve the effectiveness and safety, and to reduce the safety while being effective Sexual compromise; and in different stem regions where the region to maintain high water transport efficiency to adapt to the atmospheric CO 2 concentration.