Shade alters grass growth and architecture by reducing root biomass

Variable tree cover characterizes tropical grassy biomes. Light availability in the ground layer becomes increasingly limited as tree cover increases while open canopy environments are associated with a flammable grassy ground layer. Grass species dominating the ground layer of these ecosystems have adopted strategies to persist and proliferate with frequent fire. However, there is limited understanding of how grass growth and flammability traits respond to changes in light availability. We experimentally grew 14 grass species characteristic of the Malagasy Central Highlands for one year with four treatments of light exclusion ranging from 0 – 60%. Six plant functional traits and four leaf flammability traits were measured: plant height, bulk density, aboveground biomass, belowground biomass, ratio of root to shoot biomass, specific leaf area, leaf heat release capacity, temperature of maximum decomposition, total heat release and peak heat release rate. Belowground biomass, the ratio o...热带草本生物群系的典型特征为可变的树木盖度。随着树木盖度升高，地表层的光照可获得性逐渐降低；而开阔冠层环境则与易燃的草本地表层密切相关。主导此类生态系统地表层的草本植物，演化出了在频繁火干扰下存续与繁衍的适应策略。然而，当前学界对草本生长与易燃性性状如何响应光照可获得性变化的认知仍较为匮乏。本研究以马达加斯加中部高地特有的14种草本植物为实验材料，开展了为期1年的遮阴实验，设置了0%至60%共4个梯度的光照排除处理。本研究测定了6项植物功能性状与4项叶片易燃性性状：株高、容重、地上生物量、地下生物量、根冠比、比叶面积（specific leaf area），以及叶片释热容量、最大分解温度、总释热量与峰值热释放速率。地下生物量、根冠比（ratio o...）