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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.

叶子的寿命比个体的寿命短，植物在生长期产生并脱落叶子。叶的产生和脱落的模式是不同的物种之间的万年青和落叶物种的代表。我们认为叶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，建立了一个新的叶片动态和氮素模型。该模型预测了最佳叶面积指数，冠层光合作用，叶片寿命，氮利用效率，以及它们对氮和光可用性变化的反应。在实验建立的草本林分，我们分析了负责叶生产和脱落的因素。遮荫叶的叶面积损失率随氮素再转运量的增加而增加，以满足植株生长对氮素的需求。我们证明，叶片被丢弃烤箱，虽然保持这些叶片更长的时间将有助于植物生长在低氮可用性，而在高氮可用性叶片不丢弃，即使与叶片损失相关的氮的再转运将增加总植物生长速率。在山毛榉林，我们发现，树冠和林下树种有一个类似的N吸收率，不依赖于光的可用性。在同一林分中，林下和林冠层树种的叶片氮素利用效率差异不显著，但其作用机制不同。冠层物种具有较高的N生产力与低的平均停留时间的N，而下层物种具有较高的N停留时间与低的N生产力。研究了叶片光合作用对环境变化的响应。叶肉细胞表面的空隙空间的可用性，以容纳扩大的叶绿体是必不可少的积极响应突然增加的光气候。