Leaf traits and chloroplast structure have a direct impact on plant growth rates. Fast-growing species allocate more carbon to growth, and slow-growing species invest more in storage. This study was conducted to investigate the fast-growing mechanism of the introduced mangrove species Laguncularia racemosa, by comparing the leaves of L. racemosa and three slow-growing native mangrove species (Kandelia obovata, Avicennia marina, and Aegiceras corniculatum) through analysis of anisotropic growth of leaf traits and leaf chloroplast ultrastructure. The results showed that the largest slope values were found in the leaf area compared to leaf perimeter relationship (2.035), while the slope of the leaf perimeter compared to leaf width relationship was only 0.832. And the leaf area of A. marina was most influenced by leaf perimeter, while the leaf area of L. racemosa was least influenced by leaf perimeter. Furthermore, the average area of thylakoid lamellae per chloroplast was the largest in L. racemosa leaves, with no accumulation of starch granules detected. While most of the chloroplast area of three native mangrove species was occupied by starch granules and lipid droplets, resulting in a reduction in the thylakoid lamellae contained per unit area of the chloroplasts. These results imply that the chloroplasts of L. racemosa can transport photosynthetic products to other organs of the plant in a timely manner, maximizing the area of thylakoid lamellae in the chloroplast and enabling its leaves to maintain high photosynthesis for its rapid growth.

叶片性状和叶绿体结构对植物生长速度有直接影响。快速生长的物种为生长分配更多的碳，而生长缓慢的物种则在储存方面投入更多。本研究通过各向异性分析，比较了红树种的叶片与三种生长缓慢的本土红树种（秋茄、白骨壤和桐花树）的叶片，探讨了引进红树种Lagunulousia racemosa的快速生长机制。叶片生长性状和叶片叶绿体超微结构。结果表明，叶面积与叶周长关系的斜率最大（2.035），而叶周长与叶宽关系的斜率仅为0.832。其中A. marina的叶面积受叶周长的影响最大，而L. racemosa的叶面积受叶周长的影响最小。此外，总状叶绿体中类囊体片层的平均面积最大，且未检测到淀粉颗粒的积累。而三种本土红树物种的叶绿体面积大部分被淀粉颗粒和脂滴占据，导致单位面积叶绿体所含类囊体片层减少。这些结果表明，总状花草的叶绿体能够将光合产物及时输送到植物的其他器官，使叶绿体中类囊体片层的面积最大化，使其叶片能够保持较高的光合作用，促进其快速生长。