Jurik Thomas W, Chabot Brian F
Section of Ecology and Systematics, Cornell University, 14853, Ithaca, NY, USA.
Oecologia. 1986 May;69(2):296-304. doi: 10.1007/BF00377637.
Leaf dynamics and carbon gain were evaluated for two species of wild strawberry, Fragaria virginiana and F. vesca. Five populations on sites representing a gradient of successional regrowth near Ithaca, N.Y., U.S.A., were studied for two or three years each. A computer-based model of plant growth and CO exchange combined field studies of leaf biomass dynamics with previously-determined gas exchange rates to estimate carbon balances of leaves and whole plants in different environments.Leaves were produced throughout the growing season, although there was usually a decline in rate of leaf-production in mid-summer. Leaves produced in late spring had the largest area and longest lifespan (except for overwintering leaves produced in the fall). Specific Leaf Weight (SLW) varied little with time of leaf production, but differed greatly among populations; SLW increased with amount of light received in each habitat. The population in the most open habitat had the least seasonal variation in all leaf characters. F. vesca produced lighter, longer-lived leaves than F. virginiana.Simulations showed that age had the largest effect on leaf carbon gain in high-light environments; water stress and temperature had lesser effects. Leaf carbon gain in lowlight environments was relatively unaffected by age and environmental factors other than light. Leaves in high-light environments had the greatest lifetime profit and the greatest ratio of profit to cost. Increasing lifespan by 1/3 increased profit by 80% in low-light leaves and 50% in high-light leaves. Increasing the number of days during which the leaf had the potential to exhibit high photosynthetic rate in response to high light led to little change in profit of low-light leaves while increasing profit of high-light leaves by 49%.
对两种野生草莓——弗州草莓（Fragaria virginiana）和野草莓（F. vesca）的叶片动态和碳获取情况进行了评估。在美国纽约州伊萨卡附近选取了五个代表演替再生梯度的地点的种群，对每个种群进行了两到三年的研究。一个基于计算机的植物生长和二氧化碳交换模型，将叶片生物量动态的田间研究与先前确定的气体交换率相结合，以估算不同环境下叶片和整株植物的碳平衡。
在整个生长季节都有新叶产生，不过通常在仲夏时节叶片产生速率会下降。春末产生的叶片面积最大且寿命最长（秋季产生的越冬叶除外）。比叶重（SLW）随叶片产生时间的变化较小，但在不同种群间差异很大；比叶重在每个生境中随光照量增加而增加。在最开阔生境中的种群，所有叶片特征的季节性变化最小。野草莓产生的叶片比弗州草莓的更轻、寿命更长。
模拟结果表明，在高光环境下，叶龄对叶片碳获取的影响最大；水分胁迫和温度的影响较小。在低光环境下，叶片碳获取相对不受叶龄和除光照外其他环境因素的影响。高光环境下的叶片终生收益最大，收益与成本的比率也最大。将低光叶片的寿命延长三分之一，收益增加80%；将高光叶片的寿命延长三分之一，收益增加50%。增加叶片在高光条件下具有高光合速率的天数，低光叶片的收益变化不大，而高光叶片的收益增加49%。
