Abstract:

Dynamics of leaf mass (LM), leaf area (LA) and element retranslocation efficiency during leaf senescence was investigated in Phyllostachys pubescens Mazel ex H. de Lehaie in Yongchun, Fujian, China. Comparison of differences in element retranslocation efficiencies (RE) based on per gram leaf dry weight, per leaf and per LA during leaf senescence was carried out. With leaf senescence, the mean decreases of LM, LA and specific leaf mass (SLM) were 19.55%, 15.16% and 5.07%, respectively. The seasonal changes in decrease percentage of LM and LA were similar, indicating that certain mass to area ratios occurred in P. pubescens leaves. On different bases, RE of N and K was positive, while RE of Ca was negative, suggesting that with leaf senescence, N and K were translocated out of senescing leaves to other parts of plant, while Ca accumulated in senescing leaves. For the mean RE of N, P, K, Ca and Mg on different bases, the rank order was RE₂ (mg element/leaf)＞RE₃ (mg element/cm² leaf)＞RE₁ (mg element/g), therefore, RE on the basis of leaf weight or LA would be underestimated.

Key words: Phyllostachys pubescens , leaf mass (LM), leaf area (LA), element retranslocation efficiency, leaf senescence