三桠乌药耐阴性研究

对不同遮阴条件下盆栽三桠乌药植株生长状况以及光合特性的研究结果表明,50%左右的遮阴条件有利于三桠乌药植株的形态建成,植株形态综合评价指数为 0.91,全光照及95%遮阴条件下,植株形态综合评价指数仅为0.29及0.20。不同遮阴条件下三桠乌药叶片叶绿素a、叶绿素总量以及叶绿素a/b差异显著,但与光照强度之间无明显线性关系,而叶绿素b含量随着遮阴强度的增加而呈显著提高趋势。不同遮阴条件下三桠乌药光合速率日变化曲线差异明显,但与其生物量之间无明显线性关系。在较强光照条件下光合速率日变化曲线呈明显双峰曲线,存在“光合午休”现象。三桠乌药光合作用补偿点为12.98 μmol/(m²·s),光饱和点介于200~400 μmol/(m²·s)之间,而表观量子效率为0.0366 mol/mol,这表明三桠乌药具有较强的弱光利用的能力。

A study on the shade tolerance of Lauraceae obtusiloba

The plant morphogenesis and photosynthetic characteristics of potted Lauraceae obtusiloba were studied under different shade treatments. Fifty percent shading improved the growth and accelerated the morphological building of L. obtusiloba, and the synthetical evaluation of the growth index reached 0.91. Under natural sunlight and 95% shading, the growth indexes were 0.29 and 0.20 respectively. Under different shading treatments, the total chlorophyll content, chlorophyll a content and chlorophyll a/b showed significant differences, but there was no obvious linear relationship with light intensity. The chlorophyll b content increased gradually with the extent of shading. Under different shading treatments, the diurnal change curves of Pn varied significantly, but there was no significant linear relationship with the biomass. With adequate illumination, the diurnal change curve of Pn showed double peaks, and the photosynthesis had a significant midday depression. The light compensation point of L. obtusiloba was 12.98 μmol/(m²·s), the light saturation point was about 200-400 μmol/(m²·s), and the apparent quantum efficiency was 0.0366 mol/mol, which showed the capability of L. obtusiloba to use weak light.