【作者】 董大川；

【导师】 方伟； 高培军；

【作者基本信息】 浙江农林大学 ， 森林培育， 2011， 硕士

【摘要】 毛竹Phyllostachys pubescens是我国分布面积最广,社会、经济、生态效益较高的竹种,在我国竹产业中占有极其重要的地位。毛竹的生物蓄积量大,成材迅速,干物质的积累是与高效的光合作用密切相关的。本文从叶片水平、冠层水平和年龄水平3个维度研究探讨了近自然状态下毛竹叶片的色素含量,活体条件下的反射光谱、荧光发射光谱特性,以及叶绿素荧光动力学特性。以期能为毛竹林分结构定向调整,推进竹产业升级提供一定的试验依据。主要研究结果如下:(1)离体条件下,1龄毛竹阳生叶片的Chl a含量要比阴生叶高28.80%,5龄竹中阳生叶比阴生叶高21.58%,5龄竹中则阴生叶高于阳生叶4.89%;随着冠层高度降低,Chl a的含量逐渐增加,1龄竹下层叶片Chl a含量是上层叶片的1.24倍,3、5龄竹中叶呈现相同的趋势。在弱光环境中生长的叶片Chl b的含量相对较高,1龄竹中阴生叶Chl b的含量是阳生叶1.11倍,中层叶比上层叶高43.84%,下层比中层高50.27%;3、5龄竹中表现有类似的趋势。Chl a/b的值阳生叶>阴生叶;上层叶>中层叶>下层叶。随着竹龄的增加,叶绿素含量呈现先升高后下降的趋势,Chl a/b的值则随年龄增加而逐渐减少。(2)活体条件下,通过原始光谱和四阶导数光谱对比分析显示阳生叶Chl a高于阴生叶片,而Chl a的含量随着高度降低而减弱;Chl b的含量阴生叶较高、下层叶>中层叶>上层叶与离体条件下测量结果一致。弱光环境下,类胡萝卜素的含量相对较高,并且色素种类相应增多。(3)对毛竹叶片的荧光发射光谱就进行高斯解析显示,毛竹叶片在683nm和730nm处有两个荧光峰,分别反映了PSII和PSI的能量分配过程。弱光环境中的毛竹叶片荧光强度较强,分配至PSI的能量逐渐增多。(4)将快速荧光诱导动力学和调制荧光技术相结合能较全面的反映毛竹叶片的叶绿素荧光特性。结果显示在弱光环境下,PSII反应中心吸收捕获光能的能力增强,PSII受体侧PQ库增大,但进入电子传递链过程不同程度受阻,导致QA-还原次数增加大量积累,光合效能降低;在光适应条件下的实际光合能力和Rfd值也有不同程度的下降,相对电子传递速率降低。弱光环境对不同朝向毛竹叶片之间的影响较小,而由于冠层高度不同造成的荫庇对叶片组化生理有显著影响。(5)不同朝向的毛竹叶片,阳生叶的光合效能较高;不同冠层高度的叶片,上层叶片的光合效能高,中层次之,下层叶片最低;不同竹龄的毛竹光合效能呈现先增加后下降的变化过程。更多还原

【Abstract】 Phyllostachys pubescen, one of the most important bamboo species in China, has highly social economic and ecological value. To interpret its gorgeous growing speed and the high-efficient biomass accumulation capability, we ask for the relationship associated with photosynthesis. This study investigated characteristics of P. pubescens leaves in different directions, heights and ages by probing chlorophyll contents in vitro, reflectance spectra, fluorescence emission spectra and chlorophyll fluorescence induced kinetics (FIK) in vivo. The main results are as following:(1) In vitro condition, the contents of Chl a in sun leaves was 28.80% higher than that in shade leaves in 1-year-old bamboo; 21.58% higher than shade one in 3-year-old bamboo; in 5-year-old bamboo the contents of Chl a in shade leave was 4.89% higher than that in sun leaves. As the height went down, Chl a accumulated gradually, in 1-year-old bamboo, Chl a of leaves in lower level was 1.24 times of upper one. Similar conditions existed in 3-year-old and 5-year-old bamboos. Leaves in low-light circumstances had higher Chl b contents, in 1-year-old bamboo, the Chl b in shade leaves was 1.11 times of that in sun leaves, middle level was 43.84% higher than upper level and lower level was 50.27% higher than middle level, which was the same with that in 3-year-old and 5-year-old bamboos. Chl a/b sun leaves > shade leaves; upper level>middle level>lower level. As the age increased, the contents of chlorophyll increased and then decreased, while Chl a/b decreased graudually.(2) In vivo condition, via comparison between the raw spectral data and reflectance spectrum with 4th order derivative the result showed that sun leaves had higher Chl a content than shade leaves, while Chl a decreased with height going down.Shade leaves had more Chl b, and lower level>middle level>upper level as the same with the results in vitro condition. In low-light condition leaves would have more carotenoid and more sorts of pigments.(3) We analyzed fluorescence emission spectra by Gaussian decomposition. The result showed that 2 fluorescent peaks appeared at 683nm and 730nm, which stands for the distribution of energy in PSII and PSI separately. The fluorescence intensity was stronger and the proportion of photon distributed to PSI elevated relatively in leaves under low-light condition.(4) The chlorophyll FIK discovered that the capabilities of ABS/RC and TR/RC of leaves in low-light condition were reinforced but on donor side of PSII which had larger PQ pool traped electrons were hardly into the electron transport chain and the accumulated. The performance of photosynthesis deceased. In light adapted leaves, FV’/FM’, Rfd and ETR decreased. Influence caused by altitude level was more significant than that caused by different directions.(5) As for the efficience of photosynthesis, sun leaves and upper level leaves were better than shade and lower ones. In different aged P. pubescens the variational trends increased firstly and then dereased.更多还原