林业科学2016，Vol.52Issue(5)：55-63,9.DOI:10.11707/j.1001-7488.20160507
不同遮荫水平下香榧苗期光合作用及氮分配的响应机制
Response of Photosynthesis and Nitrogen Distribution of Torreya grandis‘Merrilli’Seedlings in Different Light Regimes
摘要
Abstract
[Objective]To elucidate the mechanism of photosynthetic characteristics and nitrogen allocation of Torreya grandis‘Merrilli’seedlings under different shading levels,the growth,gas exchanges parameters,chlorophyll content and leaf nitrogen content were measured. [Method]We measured the height,ground diameter,biomass,light response curve,CO2 response curve,chlorophyll content,leaf nitrogen content of T. grandis‘Merrilli’seedlings under different shading levels( 0%,50%,75% and 90%) .[Result]The results showed that the leaf color of seedlings became much greener with the increasing level of shade levels. However,the diameter increment and biomass of seedlings showed an increase at first,followed by a decreased trend with increasing shade level. The seedlings at 50% and 75% shade levels had the greatest diameter increment,which was 215. 2% and 233. 6% of that at 0% shade level and 161. 4% and 175. 2% of that at 90% shade level,respectively. The biomass at 75% shade level was significanly higher than the other shade treatments,and was 141. 0%,111. 5% and 114. 0% compared with that at 0%,50% and 90% shade level respectively. The root/shoot ratio of seedlings reduced gradually,while the chlorophyll a ( Chl a) ,chlorophyll b ( Chl b) and carotenoid ( Car) content increased with increasing of shade levels. LCP ( light compensation point) ,and LSP ( light saturation point ) decreased while the apparent quantum efficiency ( AQY ) increased with increasing of shade level. Maximum net photosynthetic rate ( Pmax ) , maximum RuBP carboxylation rate ( Vcmax ) and RuBP regeneration of photosynthetic electron transport rate (Jmax) showed an increase at first,followed by a decreased trend with increasing of shade level and the highest parameters were observed at 50% and 75% shade levels. However,the leaf nitrogen content per unit area ( Na ) showed a decrease trend with increasing of shade level. Moreover,the fraction of leaf nitrogen allocated to carboxylation ( N C ) ,the fraction of leaf nitrogen allocated to bioenergetics ( N B ) ,the fraction of leaf nitrogen allocated to light-absorbing pigment (NL),and photosynthetic nitrogen utilization efficiency (PNUE) showed a decrease trend with increasing of shade levels,and the highest values of these parameters except NL were observed at 75% shade level.[Conclusion]Shade treatment can effectively promote the growth of T. grandis‘Merrilli’seedlings. The seedlings grown under shade treatment can effectively use the lower light intensity at early morning or late afternoon in comparison to that grown at full sun light. Heavy shading (90% shading level) significantly decreased the Pmax,which may be related to the capacity to capture more light,and thus more resources were used to the light protein,resulting in a decline in photosynthetic capacity. Compared with the 50% shade level,the 75% shade level had more nitrogen allocated to the photosynthetic mechanism,such as in Nc and NB,and significant higher PNUE. Thus,our results indicate that T. grandis‘Merrilli’seedlings likely grow better at 75% shade level for seedling cultivation.关键词
香榧/生物量/光合特性/叶氮含量/光合氮素利用效率Key words
Torreya grandis‘Merrilli’/biomass/photosynthetic characteristics/leaf nitrogen content/photosynthetic nitrogen utilization efficiency分类
农业科技引用本文复制引用
宋洋,廖亮,刘涛,蒋燕锋,喻卫武,胡渊渊,吴家胜..不同遮荫水平下香榧苗期光合作用及氮分配的响应机制[J].林业科学,2016,52(5):55-63,9.基金项目
浙江省重中之重林学一级学科开放基金项目(KF201312) （KF201312）
浙江省林业厅科技项目“香榧大苗培育及高效生态栽培技术集成与中试示范”(2013B01) （2013B01）
浙江农林大学人才启动项目(2013FR063) （2013FR063）
浙江省农业新品种选育重大科技专项(2012C12904－12) （2012C12904－12）
浙江省科技厅重大科技专项重点农业项目“浙江西南油料干果产业化培育技术研究与示范推广”(2012C12002)。 （2012C12002）
