油松Ｐ—Ｙ曲线主要水分参数随季节和种源的变化

 借助P—V曲线，研究了油松主要水分参数(包括饱和含水时的最大渗透势φ8sat、初始质壁分离时的渗透势φ8tlp、渗透水相对含量Ftl p，和相对含水量RWCtlp，以及质外体水相对含量AWC)随季节和种源的变化。结果表明，油松P—V曲线主要水分参数是随生长发育阶段和环境条件的改变而发生变化的。其中φ8sat、φ8tlp、Ftl p和RWCtlp值在夏季生长高峰期达到最高，以后逐渐降低，到严冬季节达到一年中的最低水平，随春季来临又将升高。而AWC值表现了与此相反的季节变化趋势。油松林木主要水分参数随季节发生的变化，与林木的抗寒锻炼过程表现了很大的一致性。油松不同种源水分参数上的差异亦很明显，表现最典型的是在冬季。根据水分参数所计算的综合指标表明，在油松不同气候生态型中，抗旱性强弱的顺序是，东北型、中部型、东部型、西南型、西北型、中西型、南部型。

The Changes of Main Water Parameters in Pinus tablaeformis With Season and Provenance

The changes of main water parameters(MWP),including φ8sat (maximum osmotic potential at water saturation point), φ8tlp (osmotic potential when a plasmolysis just emerges), Ftlp (relative content of osmotic water), RWCtlp(relative water content)and AWC(relative water content in apoplast),in Pinus tablaeformis with season and provenance were studied by means of pressure-volume curve The result showed that the MWP in P-V curve of P. tablaeformis changed in response to the changes of both the growth and development stages and the environmental conditions. Among these parameters,φ8sat , φ8tlp Ftlpand RWCtlp were the highest during the stage of a growth peak in summer,then reduced gradually, and reached down to the lowest in cold winter. These parameters increased again when spring comes. However, the change trend of AWC was the opposite. Changes in MWP of P. tablaeformis with season were rather consistent with tree’s cold hardening. The difference in MWP of P. tablaeformis from different porvenances was remarkable, especially in winter. The synthetical index calculated from MWP indicated that of the climatic ecotypes of P. tablaeformis drought resistance had following order from strong to weak:northeast,central, east,southwest, northwest, centralwest and south type.