不同程度石漠化对金山荚蒾末端小枝的生长和生物量积累及分配的影响

Effects of rocky desertification on growth and biomass accumulation and distribution of terminal twigs in Viburnum chinshanense Graebn.

以金山荚蒾(Viburnum chinshanense Graebn.)末端小枝为研究对象,通过野外调查,研究不同程度(轻度、中度、重度)石漠化生境对金山荚蒾小枝的生长形态、生物量积累及分配的影响。结果表明,在石漠化地区,金山荚蒾的小枝生物量积累受到抑制,且随石漠化程度的加剧而增大,其中,小枝花的生物量相比茎、叶下降幅度最小。与无石漠化地区相比,金山荚蒾小枝的形态指标(叶片数、叶面积、比叶面积、茎长、茎径)均显著降低,且石漠化对植物小枝茎长的抑制作用大于茎径,而叶面积受到的抑制程度最大。金山荚蒾在轻度、中度石漠化地区尽可能通过提高叶生物量比、降低茎生物量比来适应石漠化生境;但金山荚蒾在3种不同程度石漠化生境中均以提高花生物量比来增加生殖投入,从而保证其繁殖能力和种群延续;其通过减小茎、叶等营养器官投资的策略来适应严苛生境,最大程度维持生态系统的格局和稳定。

Karst rocky desertification is a serious geological disaster in southwestern China.Viburnum chinshanense Graebn. shrubs were selected to study how growth of its terminal twigs responded to different degrees of rocky desertification by assessing its biomass accumulation and allocation and morphological plasticity. Results showed that in the rocky desertification area,twig biomass accumulation was significantly restrained,and the degree of restraint increased with the degree of rocky desertification. Compared with leaf and stem biomass, the decrease in flower biomass was minimal. Compared with non-rockydesertification,the morphological growth indexes（ leaf number,leaf area,specific leaf area,stem length, and stem diameter） of V. chinshanense significantly decreased, and the inhibition of rocky desertification on stem length was greater than that of stem diameter,whereas leaf area was the most inhibited. Leaf biomass and stem biomass ratios in the slight and moderate rocky desertification habitats increased as an adaptation to such habitats.However, in three of the habitats with different degrees of rocky desertification, the reproductive investment of V. chinshanense increased by increasing the flower biomass ratio to ensure reproductive capacity and population continuity. V. chinshanense uses strategies to reduce the investment of vegetative organs,such as leaves and stems,to adapt to harsh habitats and maintain ecosystem structure and stability at the maximum degree.