热带林下人工种植阳春砂仁的生长与果实产量动态

调查了西双版纳不同海拔热带沟谷雨林和次生林下的阳春砂仁生长和果实产量动态．结果表明，西双版纳热带林下阳春砂仁自身年龄增长、林下光照不足和旱季水分胁迫影响阳春砂仁果实产量。随种植期增加，阳春砂仁果实产量和成熟植株密度降低．当林下光照水平在全日照的35％以下时，阳春砂仁果实产量随林下日照水平变化呈线性增加(P<0．05)。沟谷下方阳春砂仁果实产量显著高于上方(P<0.05)。海拔600～1000m，由于阳春砂仁的主花期从干热季3～4月推迟到雨季5月，果实产量显著增加，沟谷雨林和次生林下阳春砂仁果实产量差异不显著。因此，在海拔800～1000m沟谷中轮歇地次生林下有计划种植阳春砂仁，代替在沟谷雨林下种植阳春砂仁，既能解决沟谷雨林下光照和当地旱季水分不足对阳春砂仁果实产量的影响，又有利于热带沟谷雨林的保护。

Dynamics of Amomum villosum growth and its fruit yield cultivated under tropical forests

Investigations on the dynamics of Amomum villosum growth and its fruit yield cultivated under tropical ravine rainforest and secondary forest at different elevations in Xishuangbanna showed that the yield of A. villosum was influenced by the site age, sun light level of understorey, and water stress in dry season. The fruit yield and mature plant density decreased with increasing age of the A. villosum site. The fruit yield increased with sun light level when the light level in understorey was under 35% of full sun light (P < 0.05). The fruit yield at the lower site by stream was significantly higher than that at upper site (P < 0.05). The yield difference between ravine rainforest and secondary forest was not significant. Planned cultivation of A. villosum in the secondary forest of the shifting cultivation land by ravine from 800-1000 m elevation instead of customary cultivation in the ravine rainforest, could not only resolve the problem of the effect of light deficiency in understorey and water stress in the dry season on A. villosum fruit yield, but also be useful to protect the tropical ravine rain forest.