权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Application of canopy photosythesis models to the analysis of leaf phenology

冠层光合作用模型在叶片物候分析中的应用

基本信息

批准号：
14340241
负责人：
HIROSE Tadaki
金额：
$ 9.34万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14340241/
关键词：
Leaf phenology Canopy photosynthesis models Lifespan Stratification Nitrogen use efficiency Forest Nitrogen productivity Mean residence time

项目摘要

The lifespan of leaves is shorter than that of individuals, and plants produce and shed their leaves in the growth period. The pattern of leaf production and shedding is different among species as is represented in evergreen and deciduous species. We considered difference in leaf phenology as a strategy of plants to adapt themselves to changing environments. Applying a canopy photosynthesis model to the analysis of leaf phenology, we developed a new model of leaf dynamics and nitrogen. The model predicted optimal LAI, canopy photosynthesis, leaf lifespan, nitrogen use efficiency, and also their responses to changes in nitrogen and light availability. In experimentally established herbaceous stands, we analysed the factors responsible for leaf production and shedding. Leaf area loss rate increased in shaded leaves with an increase in N retranslocation to meet the N demand for growth of the plant. We demonstrated that leaves were discarded Oven though maintaining those leaves longer would contribute to plant growth at low N availability, while at high N availability leaves were not discarded even though retranslocation of N associated with leaf loss would increase total plant growth rate. In a beech forest, we found that canopy and understorey tree species had a similar N resorption rate that did not depend on the light availability. In the same forest, we found that leaf level N use efficiency was not significantly different between canopy and understorey species, though the mechanism was very different from each other. Canopy species had a high N productivity with a low mean residence time of N, while understorey species had a high residence time of N with a low N productivity. We studied responses of leaf photosynthesis to environmental changes. Availability of vacant space in mesophyll cell surfaces to accomodate enlarged chloroplasts is indispensable to positively respond to sudden increase in light climate.

叶子的寿命比个体短，植物在生长期产生和脱落叶子。不同物种的叶子产生和脱落的模式是不同的，以常绿和落叶物种为代表。我们认为叶子物候的差异是植物适应不断变化的环境的一种策略。将冠层光合作用模型应用于叶片物候分析，我们开发了一种新的叶片动力学和氮模型。该模型预测了最佳 LAI、冠层光合作用、叶片寿命、氮利用效率，以及它们对氮和光利用率变化的反应。在实验建立的草本林中，我们分析了影响叶子生产和脱落的因素。遮荫叶片的叶面积损失率随着氮再转运的增加而增加，以满足植物生长所需的氮。我们证明了叶子被丢弃在烤箱中，尽管在低氮利用率下维持这些叶子更长时间将有助于植物生长，而在高氮利用率下叶子不会被丢弃，即使与叶子损失相关的氮的重新转移会增加植物的总生长率。在山毛榉森林中，我们发现树冠和林下树种具有相似的氮吸收率，且不依赖于光的可用性。在同一森林中，我们发现冠层和林下物种的叶水平氮利用效率没有显着差异，尽管机制彼此有很大不同。冠层物种具有较高的氮生产力和较低的氮平均停留时间，而林下物种具有较高的氮停留时间和较低的氮生产力。我们研究了叶子光合作用对环境变化的反应。叶肉细胞表面的可用空间来容纳扩大的叶绿体对于积极应对光照气候的突然增加是必不可少的。