‘凤丹’生物量分配的季节动态及其受株龄和遮荫的影响

生物量分配动态研究对了解作物产量形成机制具有重要意义。‘凤丹’是以杨山牡丹（Paeonia ostii T.Hong et J.X.Zhang）为原种形成的新型木本油料作物，其产量形成机制尚不明确。本文采取破坏性取样策略，研究不同株龄‘凤丹’生物量分配的季节动态以及遮荫对产量的影响。结果显示，‘凤丹’生物量在果熟期达到最大值，总生物量随株龄增大而增加，但其增长速率趋势则相反。‘凤丹’根和茎的生物量分配在休眠期最大，而叶生物量分配最大值出现在果熟期；繁殖分配仅为3.24%~6.85%，但随株龄增大而增加（4年生果实生物量为（7.74 ±0.31）g/株，8年生果实生物量为（26.81 ±0.44）g/株）。‘凤丹’单株年同化总量为161.21~232.34 g，种子收获指数为2.71%~6.87%，收获指数与株龄呈正相关（R²=0.8178）。‘凤丹’营养生长和总生物量在遮荫条件下有所降低，但繁殖生物量和收获指数在30%遮阳处理中显著增加（种子增产3.66 g/株，产量提高389.36%）。本研究表明‘凤丹’年周期内的源与库结构呈动态变化，株龄对‘凤丹’的生物量分配及产量有明显效应，适度遮荫可提高‘凤丹’的产量。

Seasonal dynamics of biomass allocation of Paeonia ostii ‘Fengdan’ and the effects of tree age and shading

The study of biomass accumulation and distribution is of great significance to understand the mechanisms of crop yield formation. ‘Fengdan’ is a new woody oilseed crop originated from Paeonia ostii T.Hong et J.X.Zhang, though its production mechanism remains unclear. In the study, destructive sampling was applied to test the seasonal variations in biomass accumulation and allocation of different organs of ‘Fengdan’ plant in an annual cycle between different aged populations and under different shading treatments. Plant biomass of each age and each organ varied in different seasons and reached the highest levels during the mature fruit stage. Total biomass increased with tree age, whereas the relative growth rate displayed the reverse tendency. Biomass allocation of plant parts changed in different stages; the roots and stem exhibited the highest values during bud dormancy, whereas the highest value in the leaf occurred at the mature fruit stage. The reproductive allocation was only 3.24%-6.85% of total biomass, but this increased with age (fruit biomass was (7.74 ±0.31)g/plant for a 4-year-old fruit, but (26.81 ±0.44)g/plant for an 8-year-old fruit). Total assimilation in the annual cycle ranged from 161.21 g to 232.34 g and the seed harvest index was 2.71%-6.87%, which was positively correlated with tree age (R²=0.8178). Under shading treatments, the biomass of the root, stem, leaf, or whole plant decreased slightly, but the reproductive biomass and harvest index increased significantly to 3.66 g per plant and 389.36%, respectively, under 30% shading treatment. These findings demonstrate that the source-sink relationship in the ‘Fengdan’ plant changed dynamically over the annual cycle, tree age had a significant effect on biomass allocation and yield, and moderate shading may be more suitable for growth.