种间竞争对甘草柠条生物量积累和分配的影响

Effects of Interspecies Competition on Biomass Accumulation and Allocation of Glycyrrhiza uralensis and Caragana microphylla

研究不同种植密度和不同混栽比例条件下甘草和柠条的生物量积累、分配模式及种间竞争动态。结果表明:混栽后甘草和柠条播种苗的平均单株生物量较纯栽都有所降低,柠条受种间影响的程度较甘草大。混栽甘草的根部和单株生物量较纯栽分别减少了18·12%和14·52%,地下部分受到的影响较地上部分大;混栽柠条的根部和单株生物量较纯栽分别减少了36·51%和44·74%,地上部分受到的影响较地下部分大。甘草根、茎、叶和单株生物量混栽与纯栽之间的差异都不显著;柠条根、茎、叶和单株生物量混栽与纯栽之间的差异达到显著和极显著水平。总的来说,混栽条件下甘草和柠条的相对总生物量(RYT)随着生长时间延长和密度的增大呈减小趋势。低密度混栽时,甘草和柠条表现出一定的互惠关系;高密度混栽时,二者共用资源受限,表现出相互拮抗的关系,且随着生长时间延长而加强。混栽比例不同,甘草和柠条的种间竞争率(CR)存在一定的差异,在柠条占有较大比例的处理(甘草20%;柠条80%)中,甘草的竞争力较小;在甘草占有较大比例(甘草80%;柠条20%)和两者比例相等的处理(甘草50%;柠条50%)中,甘草的竞争力均大于柠条。苗期甘草在混栽群体中具有较强的竞争优势。

Biomass accumulation, allocation pattern and dynamics interspecies competition of Glycyrrhiza uralensis and Caragana microphylla under different density and mixed planting proportion were studied. The results showed： Both average individual biomass decreased in mixed planting. Effects on C. microphyUa was greater than that on G. uralensis. Root and individual biomass of mixed planted G. uralensis were decreased by 18.12% and 14.52% respectively, influences of underground part suffered was greater; At the same time, root and individual biomass of mixed planted C. microphylla were decreased by 36.51% and 44.74% respectively, infuluences of aboveground part suffered was greater. Different of biomass of root, stem, leaf and individual weren＇ t significant between pure and mixed planted G. uralensis, while significant or high significant for stem, leaf and indivadual of C. microphyUa. Relative yield total biomass of them decreased with growth time prolonging and density increasing under mixed plant condition. They showed a accreted relationship in low mixed density and repelled relationship in high mixed density because of limited resources, which repelling effects became more obvious with the time prolong. Their interspecies competition rate was different under different mixture proportion. For treatment of C. microphylla bigger proportion （20% G. uralensis; 80% C. microphylla）, the interspecies competition rate of G. uralensis was less. For treatment of G. uralensis bigger proportion （80% G. uralensis; 20% C. microphylla） and same proportion, the interspecies competition rate of G. uralensis was bigger. G. uralensis had a bigger competitive advantage than C. microphyUa in the seedling period.