This study aimed to investigate leaf anatomy, as well as photosynthetic gas exchange, that underlie the improvement in light foraging capacity, which appears to occur in aroid vines seeking light exposure. Three levels of plant height (soil level, 3 m and 6 m) were categorised for the aroid vine Rhodospatha oblongata Poepp. to represent the transition from ground to canopy. Compared with shaded leaves, leaves exposed to high light conditions were thicker, presenting a larger, spongy parenchyma characterised by a larger transversal area of intercellular spaces. In addition to the increase in maximum CO₂ assimilation (A_max) and thicker and larger leaf lamina, we found an increased light saturation point, light compensation point and water use efficiency at 500 µmol PPFD. Nitrogen content per leaf dry mass remained constant across habitats, but A_max/N was 1.5-times greater in the canopy position than in the leaves at soil level, suggesting that CO₂ gain did not rely on an N-related biochemical apparatus. The lower δ¹³C discrimination observed at high canopy leaves corroborated the higher photosynthesis. Altogether, these results suggest that the large and exposed aroid leaves maintained carbon gain coupled with light gain through investing in a more efficient proportion of intercellular spaces and photosynthetic cell surface, which likely allowed a less pronounced CO₂ gradient in substomatal-intercellular space.

这项研究旨在调查叶片解剖以及光合气体交换，这些是光采食能力提高的基础，光采食能力的提高似乎发生在寻求光照的非环型葡萄藤中。非环状葡萄Rhodospatha oblongata Poepp的植物高度分为三个高度（土壤高度分别为3 m和6 m）。代表从地面到树冠的过渡。与遮荫的叶子相比，暴露于高光条件下的叶子更厚，呈现出较大的海绵状薄壁组织，其特征是细胞间空间的横向面积更大。除了增加最大CO ₂同化（A _max）以及较厚和较大的叶片，我们发现在500 µmol PPFD下光饱和点，光补偿点和水分利用效率都有所提高。在整个生境中，每片叶片干重的氮含量保持不变，但是在土壤水平上，冠层位置的_最大氮含量比叶片高1.5倍，这表明CO _2的获得不依赖于N相关的生化装置。下部δ ¹³在高篷叶中观察到Ç歧视证实了较高的光合作用。总而言之，这些结果表明，大而裸露的无环叶叶片可通过对细胞间空间和光合细胞表面进行更有效的投资来维持碳的获取和光的获取，这可能会使二氧化碳含量降低。气孔下细胞间隙中的_2个梯度。