两种光照下木质藤本和树木幼苗的生理生态学特征

Comparison of the eco-physiological characteristics between seedlings of lianas and trees under two light irridiances

对比研究生长在两种光照环境(4%和35%)下的7种热带木质藤本和5种常见的雨林冠层树种幼苗叶片的光合能力、色素含量和形态解剖特征。结果表明:(1)与树木相比,低光下木质藤本光合能力(Pmax)较弱,光强升高,木质藤本光合能力提高86.4%,树木提高61.5%,且木质藤本具有更高的光合能力。其光合作用光补偿点(LCP)和饱和点(LSP)较高。(2)木质藤本和树木正午光化学效率(Fv/Fm)下降,非光化学耗散(NPQ)升高。相同处理条件下,木质藤本光化学效率高于树木,正午光系统Ⅱ受到光抑制的程度较小。(3)光强升高,木质藤本和树木单位叶面积叶绿素含量减少。木质藤本比树木单位面积均具有更高的叶绿素a、叶绿素b、叶绿素总量和类胡萝卜素含量,以及更高的叶绿素a/b的比值。(4)与研究树木相比,木质藤本具有更大的叶片厚度,并且具有更大的比叶面积(SLA),反映出其较低的叶片密度。

We compared photosynthetic characteristics, pigment contents, chlorophyll fluorescences and anatomical traits in leaves of seedlings between 7 liana and 5 tree species under two light irridiances （4 and 35% of full sunlight） in a shadehouse in Xishuangbanna, SW China. The results showed that ： （1） In the low light, lianas had lower photosynthetic capacity, whilst they had the greater increasement （lianas, 86.4% ; trees, 61.5% ） in photosynthetic rates responded to the high light level. Moreover, lianas had higher light compensation point （LCP） and light saturated point （LSP） than trees. （2） Maximum efficiency of PS Ⅱ photochemistry （ Fv/Fm ） was declined and non-photochemical quenching （NPQ） was increased in the mid-day for both lianas and trees. Compared to trees under the same light level, lianas had higher Fv/Fm values and were less photo-inhibited by the midday strong light. （3） Pigment contents per unit area decreased under the high light level. Lianas had higher pigment contents （eg. chlorophyll a, chlorophyll b, total chlorophyll, carotenoid content） per unit area and ratio of chlorophyll a and b than trees. （4） Lianas had higher specific leaf area （SLA） than trees although they had thicker leaves, which indicating thatthe density of leaves of lianas is lower.