在不同海拔地区种植的红波罗花对水分的响应

The Response of Incarvillea delavayi (Bignoniaceae) Grown in Different Altitudes Subject to Water Availability

比较了高山花卉红波罗花(Incarvillea delavayi)在原产地香格里拉和引种栽培地昆明的光合作用和叶片性状对水分的响应差异。结果表明:在两个实验点光合速率(Pn)均随着土壤水分的减少而下降。移栽昆明后,在同样的水分条件下与香格里拉相比其光合速率(Pn)较低,叶绿素含量和Chla/b的比值则没有显著变化,但单位面积的叶片氮含量(LNCa)有所增加。红波罗花在昆明较低的光合速率(Pn)与较低的气孔导度(gs)和叶肉导度(gm)以及叶氮向光合机构中分配(PB、PR)减少有关。另外,移栽昆明后,当供给的水分高于土壤田间持水量的40%时,红波罗花能够正常生长,且对水分供应的响应不如在香格里拉的植株敏感,表现在当土壤的含水量为田间最大持水量的40%～85%时,光合速率、比叶重(LMA)、叶绿素含量、LNCa均比较稳定,且不同的水分处理间没有显著性差异。除此之外,红波罗花在昆明的生长存在一个水分阈值(土壤田间持水量的40%),当供给的水分低于这个阈值时,相对生长速率出现负增长。研究结果暗示红波罗花能够在较低海拔地区引种栽培。

Photosynthesis and leaf traits of lncarvill delavayi subjected to water stress were compared in Shangri-La and Kunming to develop effective strategy for domestication and cultivation. The results showed that photosynthetic rate （P.） decreased with the decreasing water availability at both study sites. After transplanted from Shangri-La to Kunming, the photosynthetic rate （P.） decreased under the same water availability condition, and the content of chlorophyll and Chl a/b ratio had no significant difference, but the leaf N content per unit area increased. The decrease in stomatal conductance, mesophyll conductance and lower nitrogen partitioning coefficients in photosynthetic apparatus contributed to the lower photosynthetic rate in Kunming. Furthermore, the response of photosynthetic performances and leaf traits of 1. delavayi subjected to water availability in Kunming was not as sensitive as that in Shangri-La. Interestingly, the growth of 1. delavayi in Kunming had a water availability threshold （40% soil field capacity） ; if soil water availability lower than this threshold, the relative growth rate became negative. The results showed that this species could be introduced to cultivate successfully at lower altitude.