高山杜鹃‘Boursault’幼苗对容器栽培的生长响应

 盆栽杜鹃幼苗的生长直接关系到成苗后品种特征的充分表达，其中容器大小的选择是杜鹃幼苗盆栽的基础环节。试验采用C1（140 mL，6.5 cm × 6.5 cm）、C2（350 mL，10 cm × 10 cm）、C3（850 mL，13 cm × 12 cm）、C4（1 400 mL，15 cm × 13 cm）和C5（2 850 mL，18 cm × 16 cm）5种规格的黑色塑料盆，对常绿高山杜鹃（Rhdodendron catawbiense‘Boursault’）1年生幼苗实施容器生长响应试验。结果显示幼苗的生长对容器容积的变化具有敏感的响应：（1）容器容积的梯度变化对幼苗光合同化产物积累、株高和叶片数的动态增长都产生了显著影响，在140 ~ 1 400 mL（C1 ~ C4）的容积范围内，幼苗的生理及形态响应与容器容积成正相关变化，以C4（1 400 mL）处理生长最为强壮；（2）容器容积的适当增大使在遮荫环境中生长的幼苗降低了光补偿点，能够在低光强下启动光合作用以增加同化产物的合成；（3）容器容积的适当增大提升了幼苗结构和功能器官的构建速度；（4）容器容积的梯度增大使幼苗地上—地下器官的生物量增加，但对改变生物量分配比例作用甚小。

Growth Responses of Rhdodendron catawbiense'Boursault'to Size-elevated Containers

The expression of ornamental characteristics of mature pot-cultivated Rhdodendron depends on the vigorous growth of plantlet and the selection on container size is a basic aspect in commercial cultivation. The elevated container sizes including C1（140 mL，6.5 cm × 6.5 cm），C2（350 mL，10 cm × 10 cm），C3（850 mL，13 cm × 12 cm），C4（1 400 mL，15 cm × 13 cm）and C5（2 850 mL，18 cm × 16 cm）were used in our experiment. The results showed that：（1）Responses to the container volume gradients were sensitively induced in biomass，growth dynamics of plant height and leaf numbers.Positive relations between physiological and morphological traits and the container sizes were presented across 140–1 400 mL（C1–C4）and the outstanding growth occurred in C4（1 400 mL）；（2）Light compensation point of photosynthesis was decreased in larger containers to accumulate more photoassimilates in partly shading condition；（3）Construction efficiency of structural and functional organs were promoted by elevated container size from 140 mL to 1 400 mL（C1–C4）；（4）Coordinative increase in biomass happened on overground and underground organs at individual level when cultivated in size-elevated containers and the allocation fraction did not be affected by the container sizes.