Allelopathic effects of walnut leaves extracts on growth and photosynthesis of Atractylodes macrocephala seedlings | 核桃叶水浸提液对白术幼苗生长及光合作用的化感效应

Chinese. 探讨不同质量浓度核桃叶水浸提液对白术幼苗生长和光合作用的化感效应。通过盆栽试验，测定0，5，50和100 mg/mL核桃叶水浸提液对白术幼苗形态指标、生物量、叶绿素含量和光合作用的影响。以质量浓度0，5，50和100 mg/mL核桃叶水浸提液处理后，白术幼苗株高增量分别为3.65，4.03，3.68和3.42 cm；地径增量分别为2.16，2.62，2.58和2.25 mm。5 mg/mL核桃叶水浸提液对白术幼苗的生长表现出明显的促进作用，其单株鲜质量达到了1.425 mg；50 mg/mL核桃叶水浸提液对白术幼苗的单株鲜质量、地上生物量、地下生物量和单株干质量均表现出微弱的抑制作用；100 mg/mL核桃叶水浸提液对白术幼苗的生长表现出明显的抑制作用，对单株鲜质量、地上生物量、地下生物量和单株干质量的抑制率分别达到了23.4%，21.7%，28.3%和23.8%。5 mg/mL核桃叶水浸提液处理下，白术幼苗叶绿素含量最高，为2.016 mg/g，50和100 mg/mL处理下其含量均有所降低；5和50 mg/mL核桃叶水浸提液对白术幼苗叶片净光合速率和气孔导度均表现出促进作用，100 mg/mL处理则表现出明显的抑制作用。核桃叶水浸提液对白术幼苗的株高、地径、叶绿素含量及净光合速率和气孔导度的影响均表现出低促高抑的双重质量浓度效应，推测叶绿素含量及光合因子的改变，是核桃叶水浸提液引起白术幼苗生长产生相应化感效应的生理机制之一。

English. The research was done in order to find out the allelopathic effects of walnut leaves extract on growth and photosynthesis of Atractylodes macrocephala seedlings. A pot experiment was conducted to test seedlings’ morphological, biomass, chlorophyll and photosynthesis indices with 0, 5, 50 and 100 mg/mL water extracts concentrations. Under 0, 5, 50, and 100 mg/mL walnut leaves water extracts concentration, the stem length increment of A. macrocephala was 3.65, 4.03, 3.68 and 3.42 cm respectively; The root collar diameter increment of A. macrocephala was 2.16, 2.62, 2.58 and 2.25 mm respectively. RI indicated that: 5 mg/mL walnut leaves water extracts showed significant stimulatory effect on A. macrocephala seedling’s growth, the fresh weight of single plant reached 1.425 mg; 50 mg/mL walnut leaves water extracts showed slight inhibitory effect on the fresh weight of single plant, biomass of above ground, under ground and dry weight of single plant. 100 mg/mL walnut leaves water extracts showed significant inhibitory effect on fresh weight, biomass of above ground, biomass of under ground and dry weight of single plant, and the inhibition rate reached 23.4%, 21.7%, 28.3% and 23.8% respectively. The chlorophyll of A. macrocephala with the highest content was 2.016 mg/g under 5 mg/mL, and their chlorophyll contents gradually decreased under 50 and 100 mg/mL. Net photosynthesis rate and stomatal conductance showed stimulatory effect under 5 and 50 mg/mL, and significant inhibitory effect under 100 mg/mL. Walnut leaves extracts have double effects on growth and photosynthesis of A. macrocephala, that is the lower concentration of walnut leaves extracts has stimulating effects and the higher concentration has inhibitory effects of all the tested indices. The change of chlorophyll, net photosynthesis rate and stomatal conductance is the more important mechanism of the allelopathy effects of walnut leaves extracts, which can affect the growth of A. macrocephala seedlings.