草业学报2025，Vol.34Issue(2)：67-80,14.DOI:10.11686/cyxb2024101
季节性雪被厚度对高山草甸4种优势晚花植物生物量分配的影响
Effects of seasonal snow cover thickness on biomass allocation of four dominant late flowering plants in an alpine meadow
摘要
Abstract
The distribution of plant biomass among individual organs indicates the allocation of assimilation products,and is a driving mechanism of the differential growth of different organs,regulated by both external environment and internal factors.In alpine ecosystems the growing season is short and seasonal snow cover is a critical environmental factor with wide ranging implications for regulation of plant growth.This study was conducted in the Minjiang River headwaters on the eastern edge of the Qinghai-Tibet Plateau,to elucidate the growth strategies under different patterns of seasonal snow cover and their biomass trade-offs.For this purpose,data were collected on the biomass allocation to different organs(roots,stems leaves and flowers)of four dominant late flowering herb species(Gentiana farreri,Cremanthodium lineare,Allium sikkimense and Gentiana hexaphylla).The findings revealed that:1)The biomass of different components of the four plant species responded differently to different snow cover thicknesses.For C.lineare,biomass of all plant organs tended to be reduced in medium snow compared to shallow snow,with the reductions significant(P<0.05)for stem and leaf biomass.Moreover,under medium snow cover,C.lineare biomass accumulation failed to meet the threshold for seed set,leading to a decrease in population size.By contrast,biomass of all plant organs of G.farreri tended to be higher in medium snow than in shallow snow,with root and leaf biomass values significantly(P<0.05)increased.Similarly,A.sikkimense plant biomass was increased in deep snow compared to medium snow with the increases significant(P<0.05)for all plant organs-roots,stems,leaves and flowers,and for plant height.In addition,A.sikkimense consistently exhibited allometric growth relationships between the above-and belowground biomass[α=0.208,α=0.262,P<0.05,where α denotes lg(above ground biomass)∶lg(below ground biomass)].Meanwhile,G.hexaphylla plant biomass and allocation to plant parts was not significantly different in deep snow from that in shallow snow.With increase in depth of snow cover,investment in reproductive organs increased,but reproductive allocation decreased,indicating size-dependency.2)Based on the response-effect trait model,the variations in plant form with different snow thickness mainly reflected different resource acquisition roles of stems and leaves,as well as the reproductive function of flowers.The niches of C.lineare,A.sikkimense,and G.hexaphylla were significantly correlated with their aboveground biomass allocation,belowground biomass allocation,and the ratio of belowground to aboveground biomass.Thicker snow cover enhanced resource availability,leading to an increased reproductive performance for A.sikkimense and a decreased one for G.farreri,whereas G.hexaphylla maintained a constant reproductive performance with change in snow cover.This demonstrates that changes in reproductive performance are governed by various factors and exhibit species-specific responses.3)When A.sikkimense is in locations with deep snow,it faces a'seed-risk'scenario.By raising the reproductive investment,it boosts its absolute investment in reproductive organs,exemplifying the traits of a classic late-flowering alpine self-pollinating plant.Conversely,G.farreri,a cross-pollinating species,reduces its reproductive investment in moderately snowy areas rich in resources,following a strategy known as pollen-risking.关键词
岷江源区/气候变化/繁殖分配/异速生长/生长策略Key words
Minjiang headwater region/climate change/reproductive allocation/allometric growth/growth strategies引用本文复制引用
张宁,王金牛,罗栋梁,张林,徐波,吴彦..季节性雪被厚度对高山草甸4种优势晚花植物生物量分配的影响[J].草业学报,2025,34(2):67-80,14.基金项目
西北生态环境与资源研究院冰冻圈科学国家重点实验室(SKLCS-OP-2021-06),中国国家自然科学基金项目(31400389,31971436)和中国科学院西部之光西部青年学者项目(2021XBZG_XBQNXZ_A_007)资助. （SKLCS-OP-2021-06）
