石漠化生境中两种不同光合类型植物的生长和生物量分配策略

Growth and Biomass Distribution Strategies of Two Photosynthetic Plants in Rocky Desertification Habitats

【目的】研究喀斯特不同石漠化生境中不同光合类型植物的生长和生物量分配策略,为喀斯特的石漠化治理和恢复提供参考。【方法】野外采集研究区内不同石漠化生境下的C3植物三脉紫菀(Aster ageratoides)和C4植物狗尾草(Setaria viridis),测定两种植物的株高、叶面积、根系表面积等形态特征及根、茎、叶、花等各器官生物量的积累和分配。【结果】随着喀斯特石漠化程度的加剧,C3植物三脉紫菀和C4植物狗尾草的株高、叶面积及地上生物量(茎、叶、花)显著降低,但根表面积保持不变,且根和叶生物量比升高,茎生物量比降低。三脉紫菀的根生物量和总生物量并没有随着石漠化程度的加剧而降低,但狗尾草却显著降低。【结论】C3植物三脉紫菀和C4植物狗尾草在喀斯特石漠化生境中,地上生长均受到了不同程度的抑制,但都能通过提高根和叶生物量分配而降低茎生物量分配、同时保持一定的繁殖输出来适应喀斯特生境。但是,C3植物三脉紫菀在石漠化生境中表现出了比C4植物狗尾草更强的竞争力,具体原因还需进一步研究。

[Purposes]Explore the ecological adaptability of plants in different rocky desertification habitats and provide reference for the management and restoration of karst ecosystem.[Methods]C3 plant Asteris ageratoides Turcz.and C4 plant Setaria viridis(L.)Beauv.were selected to study the effects of different rocky desertification levels on the morphological characteristics,biomass accumulation and distribution of the two plants.[Findings]With the intensification of the karst rocky desertification,the plant height,leaf area and aboveground biomass(steams,leaves and flowers)of both species decreased significantly,but the root surface area didn’t change.Leaf biomass ratio and root biomass ratio of both species tended to increase while leaf biomass ratio decreased.The root biomass and total biomass of A.ageratoides did not decrease with the increase of rocky desertification,however,those of S.viridis decreased significantly.[Conclusions]The growth of aboveground in both species was restrained in the karst habitat.However,both of them could adapt to karst drought habitat by increasing the investment of root and leaf,but reducing the investment of stem and maintaining a certain propagation output.C3 plant A.ageratoides presented stronger competitiveness than C4 plant S.viridis in stony desertification habitats.The specific reasons need further study.