【摘要】 模拟林冠层郁闭情况,对不同遮荫条件下扁穗牛鞭草Hemarthria altissima的净光合速率和生长特征的研究表明:影响扁穗牛鞭草光合速率最关键因子是光照强度,在遮荫梯度16%~60%时,每增加1%遮荫度光合速率的平均减幅最小,为0.16μmol CO2/(m2.s);扁穗牛鞭草对光能利用能力较高的遮荫度范围是遮荫梯度48%~60%,其中遮荫度55%时最高,是0.038 902μmol CO2/μmol光量子;每增加1%遮荫度对生物量降低率影响最小的遮荫梯度为48%~60%,影响率为0.17%,由此可初步认为生产中林(竹)+扁穗牛鞭草退耕种植模式中林(竹)冠层的郁闭度可以考虑在0.48~0.60。更多还原

【Abstract】 An experiment was carried out to study the Pn and growth characteristics of Hemarthria compressa（L.f.） under different simulated shade densities,the results showed that the key influence factor to Pn is light intensity,The minimum change range of Pn is between the shade density of（16%～）60%.When the shade density was increased by 1%,the Pn change unit is only 0.16 μmol CO₂/（m²·s）;the shade range of high light energy utilization ratio（Pn/Par） is between the density of 48%～60%,the highest value is（0.038 902） μmol CO₂/μmol light quantum when shade density is 55%;the minimum change rate of Pn/Par is only 0.17% when the shade density was increased by 1% within the shade density range of 16%～60%.As analyzed above,the appropriate canopy shade of 0.48～（0.60） maybe OK to the practice.更多还原