遮阴对荔枝光合特征及矿质营养积累的影响  

Effects of shading on photosynthetic characteristics and mineral nutrition in Litchi

作　　者：周琳耀[1] 莫伟平[1] 张静逸[1] 黄俊波[1] 贝学文[1] 付欣雨[1] 王惠聪[1] 黄旭明[1] 

机构地区：[1]华南农业大学园艺学院,广州510642

出　　处：《果树学报》2014年第2期270-275,共6页Journal of Fruit Science

基　　金：国家自然科学基金(31171199);广东省大学生创新实验项目

摘　　要：【目的】揭示荔枝对低光照的响应和适应生理机制。【方法】以5 a生‘桂味’荔枝盆栽苗为材料,观测遮阴对新梢生长、叶片形态、光合作用和矿物质含量的影响。【结果】90%遮光率的全株遮阴处理显著抑制新梢伸长,导致新叶和老叶比重显著降低,成熟叶片净光合速率(Pn)、气孔导度(Gs)明显下降,而叶肉二氧化碳浓度(Ci)不降反略升,同时,使成熟叶片叶绿素指数(SPAD)及Fv/Fm显著增加。遮阴处理还使新、老叶片的矿质营养含量普遍提高,硝态氮:铵态氮的比值显著提高。持续遮阴导致叶片由老叶向新叶逐渐枯萎,遮阴45 d导致植株死亡。【结论】遮阴可引起荔枝叶片形态适应性变化和光能利用效率提高,其光合作用速率降低与气孔关闭及暗反应弱化等非气孔因素密切相关;遮阴导致矿质营养大量动员到叶片,但抑制硝酸还原;荔枝为不耐阴植物,长期遮阴可导致植株衰退死亡。[Objective]The purpose of this study was to understand the adaptability of litehi to low light condition. [Method]In this study, 5-year-old potted trees of Litehi chinensis Sonn. ＇Guiwei＇ were used as experimental materials to examine the effects of whole tree shading on shoot growth, leaf morphology, photosynthesis and mineral nutrition. [Result]The results showed 90% shading treatment significantly re- duced the shoot length, specific leaf weight, net photosynthetic rate （Pn）and stomata conductance （Gs） while significantly increased leaf SPAD and Fv/Fm. Although Gs was reduced by shading, mesophyll CO2 concentration （Ci）was not reduced but increased slightly. Meanwhile, most of minerals in leaves of shad- ed trees increased with significantly lower ratio of ammonium nitrogen to nitrate nitrogen. Constant whole tree shading treatment caused leaf withering from older to younger leaves and resulted in tree death at 45 days. [Conclusion]The results suggested that leaves of litchi underwent morphological and physiological changes to adapt low light condition with development of a better light capture system. However, non- stomata limiting factors such as weakened dark reaction of photosynthesis as well as closure of stomata contributed to the reduced photosynthetic capacity. Tree resources were mobilized to the leaves and nitrate reduction was significantly inhibited by shading. Litchi is a shade-intolerant tree species and long-term whole-tree shading induces tree declining and death.

关 键 词：荔枝 遮阴 光合作用 矿质营养 暗适应 

分 类 号：S667.1[农业科学—果树学]