Responses Of Acer Catalpifolium Seedlings To Light Intensity And Soil Moisture

Acer catalpifolium is a unique wild endangered plant in China.Currently,no research has addressed its endangered status from the perspective of its photosynthetic mechanism.The seedlings of Acer catalpifolium seedlings were studied to explore were selected as the research objects.The growth indexes such as plant height and baseal diameter,physiological indicators such as net photosynthetic rate and light saturation point were selected to compare the growth traits and photosynthesis of different sources of Acer catalpifolium seedlings under two light environments,and difference in light response curves of Acer catalpifolium between current-year and one-year needles.In addition,we were studied diurnal dynamics of photosynthetic parameters,light responsecurves and growthdynamics of Acer catalpifolium seedlings under three light treatments and three soil moisture conditions to explore the optimal illumination and soil moisture optimum light environment,revealing the adaptation strategy of Acer catalpifolium.Then we can analyze the endangered status of Acer catalpifolium,and propose protection measures.The research conclusions are as follows:1.The initial judgment of low light under canopy maybe the limiting factor for natural regeneration of Dayi Acer catalpifolium populations.Compared with other provenances,Leibo Acer catalpifolium seedlings are more shaded.Dujiangyan and Emeishan Acer catalpifolium have better light adaptability and growth source,and can be used as high-quality source for transplant protection.2.The light intensity had a great influence on the seedlings of A.catalpifolium,which was the main limiting factor for the growth of A.catalpifolium,and the soil moisture had little effect on the seedlings of A.catalpifolium.Under full light treatment,the utilization of light by A.catalpifolium was relatively narrow,and the light adaptation ability was weak,while the ability of seedlings to adapt to light environment was the worst under 60%shading rate.Under moderate shading conditions,A catalpifolium seedlings not only have better utilization of light,but also provide a good growth environment.Excessive shading can not conducive to the growth of A.catalpifolium seedlings.3.Under different treatments,the seedlings ofA.catalpifoliuo have midday depression phenomenon of photosynthesis.The phenomenon was affected by stomatal and non-stomatal limitation.Under the full illumination,the phenomenon in A.catalpifolium seedlings was mainly caused by stomatal limitation.Under the condition of 30%of full shade and 60%of full shade,the midday depression of photosynthesis was due to the non-stomatal limitation.4.In different light conditions,the seedlings of A.catalpifolium had the longest growth period under full light conditions,but the growth quality was slightly worse.At 30%of full shade,the seedlings grew well in the earfy stage,and the growth was slow in the later stage with the extension of the growth cycle.In the 60%shading environment,the seedling growth was the worst.The phenomenon indicated that moderate shading is beneficial to the growth and development of A.catalpifolium seedlings,but it is difficult to obtain good growth of seedlings when the light conditions are too weak.5.The optimal light environment of A.catalpifolium seedlings is 30%of full shade,and the optimum soil moisture is 55%soil moisture content.In the future,A.catalpifolium may be moderately shaded in the in situ conservation and ex situ conservation,or we can shade A.catalpifolium seedlings at noon.