【摘要】 通过设置3个光照强度,模拟森林幼苗生长的旷地、林窗和林下光环境,研究了不同透光率(100%、50%和15%)对外来种台湾桤木幼苗的生长和生理特性的影响。研究表明,随着遮阴强度的增加,台湾桤木幼苗的株高和基径呈先升高后降低的趋势;净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)逐渐降低,而胞间CO2浓度(Ci)增大。在不同的遮阴条件下,叶绿素a(Chla)、叶绿素b(Chlb)和总叶绿素含量随着透光率的降低而升高;类胡萝卜素(Car)含量、叶绿素a/b(Chla/b)和比叶重(LMA)则反之。随着光照强度的降低,台湾桤木幼苗叶片的可溶性糖先降低后升高,脯氨酸(pro)含量逐渐增加。由此表明,台湾桤木幼苗不能适应林外强光,适度遮阴的林窗有利于生长,这为造林育苗和植被恢复提供了科学参考。更多还原

【Abstract】 In order to understand the effects of shading on the growth of Alnus formosana,100%,50% and 15% of transmittance were simulated according to the light regimes in the forest opening,forest gap and forest canopy.Studies were made of the growth and physiological characteristics of A.formosana seedlings planted in different shading treatments.The results showed that with shading intensity increasing,plant height and base diameter showed the trend of first increasing and then decreasing,while net photosynthetic rate(Pn),transpiration rate(Tr)and stomatal conductance(Gs)gradually reduced except for intercellular CO2 concentration(Ci).Under different shading conditions,chlorophyll a(Chla),chlorophyll b(Chlb)and total chlorophyll content increased with transmittance decreasing,however,carotenoids(Car)content,chlorophyll a/b(Chla/b)and lamina mass per unit area(LMA)were opposite.In addition,with the reduction of light intensity,soluble sugar exhibited first decreasing and then increasing,while proline(pro)content gradually increased in leaves of A.formosana seedlings.Therefore,it was suggested that A.formosana seedlings could not adapt to the high-light environments outside forest,but moderate shading,that is to say,canopy gaps would benefit the seedling growth.At the same time,it also provided a scientific reference for forestation,breeding and vegetation recovery.更多还原