非结构糖在柠条(Caragana korshinskii K.)再生生长和持续生存中的作用

Role of Carbohydrate Reserves in Regrowth and Persistence of Caragana korshinskii K.

柠条在地上组织破坏后从根颈处萌蘖出大量的一年生枝,根系储存的碳水化合物将供应地上生长。但连续刈割后根系储存物质如何变化,储存物质在柠条生长和维持存活中的作用仍须研究。本文在不同时间段内对柠条新萌蘖枝进行连续去除(处理1:对照,3月28日刈割1次后不再处理;处理2:从萌芽到6月9日,每3 d去除一次新萌发枝;处理3:从萌芽到6月24日,每3 d去除一次新萌发枝;处理4:从萌芽到7月15,每3 d去除一次新萌发枝)。结果表明:处理3和4在7月非结构糖含量显著高于处理1和2,说明处理1和2将根系储存的非结构糖用于地上生物量的恢复。连续刈割处理(处理3和4)导致柠条根系非结构糖含量持续下降,这主要是由根系呼吸作用引起。秋末对当年生枝统计结果表明,各处理之间当年生枝数/刈割枝在各处理间差异不显著,说明柠条对外界的破坏具有极强的忍耐能力。

Caragana korshinskii K. typically develops a stout tap-root from the crown following destruction of aboveground shoots, when non-structural carbohydrate （TNC） from roots will supply for the aboveground growth. However, very little is known about the effect of consecutive clipping on resource change in roots and about the role of TNC in the growth and persistence. Consecutive clipping would remove all current year growth tissues, including stem and leaves, and result in no photosynthesis. The study included 4 treatments： treatment 1-control, shrubs were kept intact after clipping on 28 March; treatment 2-removed all aboveground tissues every three days from first sprout to 9 June; treatment 3-removed all aboveground tissues every three days from first sprout to 24 June; treatment 4-removed all aboveground tissues every three days from first sprout to 15 July. Results showed that treatment 3 and treatment 4, with higher starch concentrations, had higher TNC levels than treatment 1 and treatment 2 during July, suggesting that root reserves of C. korshinskii K. were used to support aboveground growth. Consecutive clipping reduced TNC levels in roots in treatment 3 and treatment 4, suggesting that root reserves were mainly used to maintain shrub＇s persistence. During late autumn, we counted current year shoot number of each shrub and calculated current year shoots per removed shoot, the result showed that there was no statistical difference between treatments, suggesting that C. korshinskii has strongly ability to tolerate damage.