遮荫对杉木幼苗光合生理特性及生长的影响

Effects of Shading on Photosynthetic Physiological Characteristics and Growth of Cunninghamia lanceolata Seedlings

  • 摘要: 为探究不同遮荫环境下杉木幼苗叶片光合气体交换参数、非结构性碳水化合物和养分积累变化特征,阐明其光适应机制,以180 d的杉木(Cunninghamia lanceolata)优良实生幼苗为材料,比较不同遮荫强度(0%、30%、50%、70%、90%)对杉木幼苗生长和光合气体交换参数、Rubisco酶活、叶片非结构性碳水化合物含量、植株以及土壤矿质养分含量的影响。结果表明:杉木幼苗苗高增长量、PnTrGsCi整体趋势均随遮荫强度的增大呈先升后降趋势,而地径增长量则逐渐减小,Rubisco酶活则随遮荫强度增加呈增大趋势;在50%遮荫下,杉木幼苗叶片非结构碳含量最高,显著高于全光照和90%遮荫,分别较二者提高7.7%和76.9%;遮荫处理提高了植株中磷、锰、镁、钙和钾元素的含量,降低了植株中铁元素含量;遮荫对土壤中矿质养分元素含量影响不显著。综合结果表明,光强显著影响杉木苗高和地径生长,适度遮荫处理(50%遮荫)可以增强杉木幼苗植株光合能力并改善其生长,从而提高苗木质量。

     

    Abstract: In order to explore the characteristics of photosynthetic gas exchange parameters, non-structural carbohydrates, and nutrient accumulation in the leaves of Cunninghamia lanceolata seedlings under different shading environments, this study aimed to elucidate the light adaptation mechanism of C.lanceolata.6-month-old superior seedlings of C.lanceolata grown from seeds were subjected to five shading intensities: 0%(Z0),30%(Z1),50%(Z2),70%(Z3),90%(Z4).The growth, characteristics of photosynthetic gas exchange parameters, Rubisco enzyme activity, non-structural carbohydrate content in leaves, as well as mineral nutrient content in seedlings and soil were investigated.The results showed that the overall trend of seedling height increment, Pn,Tr,Gs and Ci increased at first and then decreased with the increase of shading intensity, whereas the increment of ground diameter decreased gradually with the increase of shading intensity, and the activity of Rubisco increased with the increase of shading intensity; under Z2 treatment(50% shading),the non-structural carbohydrate content in the leaves was the highest, which was significantly higher than that of full light and 90% shading, with increases of 7.7% and 76.9%,respectively; shading treatment increased the contents of phosphorus, manganese, magnesium, calcium, and potassium in seedlings, while decreased iron content.However it had no significant effect on soil mineral nutrient contents.In conclusion, light intensity significantly affected the growth of seedling height and ground diameter of C.lanceolata,and moderate shading(50%)enhanced the photosynthetic capacity and improved the growth of C.lanceolata seedlings, thereby improving seedling quality.

     

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