Scaling relationship between total leaf size and total number of leaves per culm of Semiarundinaria densiflora

BACKGROUND AND AIMS: Leaf size and the total number of leaves per shoot (NT) reflect plant resource allocation strategies. Although studies often focus on single leaves, the leaf scaling relationships at the whole-shoot level are less known, especially in species with vertical leaf arrangements. This study investigates how total leaf area (AT), total leaf dry mass per shoot (MT) and NT scale with each other in the bamboo Semiarundinaria densiflora, which has a near-vertical foliage structure. METHODS: We sampled 121 culms with over 9200 leaves and measured AT, MT, NT and maximum individual leaf area per culm (Amax). The scaling relationships were examined using reduced major axis regression protocols. The distribution of NT was modelled with a negative binomial distribution. KEY RESULTS: N T fitted a negative binomial distribution. AT and MT scaled allometrically with NT, with scaling exponents >1. AT scaled isometrically with both the product of NT and Amax and with MT. CONCLUSIONS: The vertical foliage in S. densiflora leads to self-shading, promoting larger, thinner basipetal shade leaves. This results in a disproportionate increase in AT with NT and an isometric AT vs. MT relationship, which contrasts with the 'diminishing returns' pattern seen in individual leaves. Canopy architecture therefore is key in shaping biomass allocation.