Comparative physiology of plant adaptation: resource acquisition and constraints of growing season length in balsam poplar from temperate, boreal and arctic environments

植物适应的比较生理学：温带、寒带和北极环境中香脂杨的资源获取和生长季节长度的限制

• 批准号: 41168-2010
• 负责人: Guy, Robert
• 金额: $ 3.06万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=544847
• 关键词: Comparative; physiology; plant; adaptation; resource

There is a trend toward higher photosynthetic rates in northern populations of several angiosperm tree species that may help compensate for short summers. We recently reported that greater photosynthesis in high latitude balsam poplar results from increased leaf mass and nitrogen per area, supported by an enhanced mesophyll conductance (gm). Mesophyll conductance is a measure of the ease with which CO2 travels through leaves, but its estimation is very uncertain and must be verified. An MSc student will use an on-line isotope discrimination technique to confirm and extend these observations in controlled north-south crosses of balsam poplar. We will compare balsam poplar with black cottonwood, which also shows enhanced photosynthesis in northern genotypes, but supported by a higher stomatal conductance (gs). Increased gs can improve nitrogen-use efficiency but reduces water-use efficiency. In contrast, increased gm should improve both. These different strategies may reflect differences in water supply, which is less limiting for black cottonwood from the northwest coast than for balsam poplar from the continental interior. Along other lines, we have established common gardens of a range-wide collection of balsam poplar at Vancouver and at similar latitude in Saskatchewan. Regardless of origin, all genotypes flush, grow and set bud ~5 weeks earlier in Vancouver. Consequently, although boreal trees can take advantage of earlier springs, they may capture less of the summer. At very high latitudes, these inherent responses could lead to strong negative impacts on tree growth if climate warming is sufficient to induce flushing a few extra weeks before the solstice. We will acquire data from field and chamber experiments to model these relationships. Finally, a PhD student will test assumptions that allow information on nitrogen uptake efficiency, sites of assimilation and ion flux to be extracted from N isotope discrimination data. He will examine phytogeographic patterns in source preference, discrimination and transcript abundance (nitrate and ammonium assimilation and transport gene families) in balsam poplar from warmer, high pH, nitrate-dominated soils vs. trees from colder, low pH, ammonium-dominated soils.

在几种被子植树种的北部人群中，有一个较高的光合率有一种趋势，这可能有助于弥补短暂的夏季。 我们最近报道，高纬度香脂白杨的光合作用是由每面积增加的叶子质量和氮的增加，并由增强的叶肉电导（GM）支持。 叶叶叶电导是二氧化碳在叶子中行驶的易度性的量度，但其估计是非常不确定的，必须验证。 MSC的学生将使用在线同位素歧视技术来确认和扩展这些观察结果，以在巴尔萨姆杨树的受控南北十字架中进行。 我们将将香脂杨与黑棉木进行比较，黑杨木也显示了北部基因型的光合作用，但得到了较高的气孔电导（GS）的支持。 增加的GS可以提高氮的使用效率，但可以降低水利用效率。 相比之下，GM的增加应该改善两者。 这些不同的策略可能反映了供水的差异，这比西北海岸的黑杨木限制要比大陆室内的香脂杨树的限制要少。 沿着其他线条，我们在温哥华建立了整个范围内的香脂杨树集，在萨斯喀彻温省类似的纬度上建立了共同的花园。 无论起源如何，所有基因型都会冲洗，在温哥华5周之前生长并设置芽。 因此，尽管北方树可以利用较早的弹簧，但它们可能会占据夏天的较少。 在很高的纬度下，如果气候变暖足以在冬至前几周额外诱发潮红，这些固有的反应可能会对树木生长产生强烈的负面影响。 我们将从现场和室内实验中获取数据，以建模这些关系。 最后，博士生将测试允许从N同位素歧视数据中提取有关氮摄取效率，同化和离子通量的信息的假设。 他将在源偏好，歧视和转录物丰度（硝酸盐和铵同化和转运基因家族）中研究地理模式，该模式来自温暖，高pH，硝酸盐占主导地位，硝酸盐占主导地位的土壤与寒冷，低pH，低pH，含氨基含量的土壤的树木。