Chitwood Daniel H, Mullins Joey, Migicovsky Zoë, Frank Margaret, VanBuren Robert, Londo Jason P
Department of Horticulture, Michigan State University, East Lansing, MI, 48824, USA.
Department of Computational Mathematics, Science & Engineering, Michigan State University, East Lansing, MI, 48824, USA.
Am J Bot. 2021 Apr;108(4):571-579. doi: 10.1002/ajb2.1639.
As a leaf expands, its shape dynamically changes. Previously, we documented an allometric relationship between vein and blade area in grapevine leaves. Larger leaves have a smaller ratio of primary and secondary vein area relative to blade area compared to smaller leaves. We sought to use allometry as an indicator of leaf size and plasticity.
We measured the ratio of vein-to-blade area from the same 208 vines across four growing seasons (2013, 2015, 2016, and 2017). Matching leaves by vine and node, we analyzed the correlation between the size and shape of grapevine leaves as repeated measures with climate variables across years.
The proportion of leaf area occupied by vein and blade exponentially decreased and increased, respectively, during leaf expansion making their ratio a stronger indicator of leaf size than area itself. Total precipitation and leaf wetness hours of the previous year but not the current showed strong negative correlations with vein-to-blade ratio, whereas maximum air temperature from the previous year was positively correlated.
Our results demonstrate that vein-to-blade ratio is a strong allometric indicator of leaf size and plasticity in grapevines measured across years. Grapevine leaf primordia are initiated in buds the year before they emerge, and we found that total precipitation and maximum air temperature of the previous growing season exerted the largest statistically significant effects on leaf morphology. Vein-to-blade ratio is a promising allometric indicator of relationships between leaf morphology and climate, the robustness of which should be explored further.
随着叶片展开，其形状会动态变化。此前，我们记录了葡萄叶片中叶脉与叶片面积之间的异速生长关系。与较小的叶片相比，较大的叶片中主脉和次脉面积与叶片面积的比值更小。我们试图将异速生长作为叶片大小和可塑性的指标。
我们在四个生长季节（2013年、2015年、2016年和2017年）测量了同一208株葡萄藤的叶脉与叶片面积的比值。通过葡萄藤和节位匹配叶片，我们将葡萄叶片的大小和形状之间的相关性作为重复测量，并与多年的气候变量进行分析。
在叶片展开过程中，叶脉和叶片所占叶面积的比例分别呈指数下降和上升，这使得它们的比值比面积本身更能有力地指示叶片大小。前一年而非当年的总降水量和叶片湿润小时数与叶脉与叶片的比值呈强烈负相关，而前一年的最高气温呈正相关。
我们的结果表明，叶脉与叶片的比值是多年来测量的葡萄叶片大小和可塑性的一个强有力的异速生长指标。葡萄叶片原基在出现前一年的芽中开始形成，我们发现前一个生长季节的总降水量和最高气温对叶片形态的统计学影响最大。叶脉与叶片的比值是叶片形态与气候之间关系的一个有前景的异速生长指标，其稳健性应进一步探索。
