摘要
为了研究网室遮荫栽培对两个木瓜品种光合作用的影响,我们利用便携式光合仪测定了木瓜的光合作用日变化、光响应曲线以及叶绿素荧光.结果表明①光合作用日进程中,网室内的气温(Ta)、光强(PFD)及叶内外蒸汽压差(VPD)在中午都显著低于网室外(P≤0.05).网室内栽培的木瓜的光合速率(An)、气孔导度(gs)、细胞间CO2浓度(Ci)都出现“双峰曲线”,即未出现“午休”,而网室内栽培的正好相反.②在网室外自然光照下两种木瓜gsVPD响应VPD升高时,gs下降,呈显著负相关,这也是中午光合速率受到限制的原因之一.而网室栽培gsVPD相关不显著(P≤0.05).③网室内木瓜的叶绿素荧光FvFm午间的下降幅度显著低于网室外木瓜(P≤0.05).④网室内木瓜光响应曲线中光补偿点(LCP)和光饱和点(LSP)低,表观量子效率()高的特征,表明木瓜在网室适度遮荫的条件下的耐荫的适度性表现.以上表明在华南地区,网室栽培有助于缓解植物在中午的强光、高温以及高湿的条件下产生的光抑制,避开“午休”,从而积累更多的有机碳,提高光合效率,具有推广的潜力.
To study the effects of network shaded planting model on photosynthesis of Carica papaya , the authors measured their diurnal photosynthesis, light response curves and chlorophyll fluorescence. The results suggest that: 1) In the photosynthetic diurnal courses of C. papaya, the air temperature (T a), photosynthetic flux density (PFD) and leaf to air vapor pressure deficit (VPD) at noon in the network are significantly lower than those outside( P ≤0.05). Outside the network, the diurnal courses of net assimilation rate (A n), stomatal conductance ( g s) and intercellular CO 2 concentration (C i) were all have “two peaked curves', i.e. there are “noon breaks', while only “one peaked curves' in the network.2) Outside the network, the g s VPD responses of C.papaya show significantly negative relationships, while in the network, the g s VPD responses are not signiticant( P ≤0.05). It can partly explain the limited A n at noon. 3) F v/ F m of C.papaya in the network has a significantly less reduction at noon than that of outside. 4) In the network, both light compensation point (LCP) and light saturated point (LSP) in light responses are lower than those outside the network, but apparent quantum yield () is higher. It implies that plants growing in weak light environment could use light more efficiently and adapt themselves to be more shade tolerant. It suggests that network shaded planting model is a promising approach for C. papaya in southern China, it will be helpful for mitigating the stress of high light, air temperature and humidity at noon, escaping from “noon break' and accumulating more carbon, improving the photosynthetic efficiency.
出处
《北京林业大学学报》
CAS
CSCD
北大核心
2004年第6期57-61,共5页
Journal of Beijing Forestry University
基金
国家重点基础研究发展项目(G2000046803)
广东省科技厅星火计划资助项目(C20203)
广东省自然科学基金重点项目(021536)
广东省科技百项工程项目(2KB068015)共同资助.
关键词
网室栽培
木瓜
光合作用
光合午休
network planting, Carica papaya , photosynthesis, photosynthetic noon break
