Stomatal response of Pinus sylvestriformis to elevated CO2 concentrations during the four years of exposure

Four-year-old Pinus sylvestriformis were exposed for four growing seasons in open top chambers to ambient CO2 concentration (approx. 350 μmol·mol-1) and high CO2 concentrations (500 and 700 μmol·mol-1) at Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences at Antu Town, Jilin Province, China (42oN, 128oE). Stomatal response to elevated CO2 concentrations was examined by stomatal conductance (gs), ratio of intercellular to ambient CO2 concentration (ci/ca) and stomatal number. Reciprocal transfer experiments of stomatal conductance showed that stomatal conductance in high-[CO2]-grown plants increased in comparison with ambient-[CO2]-grown plants when measured at their respective growth CO2 concentration and at the same measurement CO2 concentration (except a reduction in 700 μmol·mol-1 CO2 grown plants compared with plants on unchambered field when measured at growth CO2 concentration and 350 μmol·mol-1CO2). High-[CO2]-grown plants exhibited lower ci/ca ratios than ambient-[CO2]-grown plants when measured at their respective growth CO2 concentration. However, ci/ca ratios increased for plants grown in high CO2 concentrations compared with control plants when measured at the same CO2 concentration. There was no significant difference in stomatal number per unit long needle between elevated and ambient CO2. However, elevated CO2 concentrations reduced the total stomatal number of whole needle by the decline of stomatal line and changed the allocation pattern of stomata between upper and lower surface of needle.

一个复杂边值问题的解

一引言随着微波理论和技术的迅速发展,对新型传输线的研究提出了更高的要求。一系列新型的微波转换过渡部件、微波滤波器和新型定向耦合器的研究,是建立在对新型传输线的理论分析基础之上的。因此,分析菱形外导体—椭园内导体传输线(以下简称外菱—内椭传输线)具有一定的理论意义和实用意义。这种传输线具有极化面固定、功率容量较大等优点。由于其截面复杂,因而无精确解,至今未见专文论述。本文采用“特征点图形逼近法”(具体方法见下文),导出特性阻抗和分布电容的计算公式,并由此推出在特定条件下的另外五种传输线的特性阻抗计算公式。所得结果均用初等函数表示,并附有部分计算结果,以供参考。