| Plant allelopathy exits in the entire nature. Studying allelopathy is helpful to scientific plant configurations, promoting biodiversity and maintaining sustainable development of the entire ecosystem. This study chose Brassica chinensis to explore the allelopathy of Eucalyptus grandis leaf litter. Through potted-Eucalyptus grandis leaf litter treatment and potted-Eucalyptus grandis leaf litter soak liquid treatment, the effects of allelopathy materials released by Eucalyptus grandis leaf litter in soils on growth and resistance of Brassica chinensis were studied. Experiment design were consisted with CK, three treatments of litter and three treatments of soak liquid which respectively were:0g-pot-1(CK),30g-po-1(D1),60g～pot-1(D2),90g·pot-1(D3),30g·pot-1(A1),60g·pot-1(A2) and90g·pot-1(A3)(D represents leaf litter treatment and A represents soak liquid treatment). Height, biomass and resistance physiological factors were measured at day20,40and80after planting. Photosynthesis factors were also measured at day80. The study results were as follows:Within the80days experiment duration after planting, all three leaf litter treatments significantly inhibited the height, leaf growth and biomass accumulation (P<0.05) and such effect increased as the treatment time prolonged. The effect of inhibition among three leaf litter treatments was insignificant (P>0.05). Soak liquid treatments experiments showed:20d after planting, merely A2presented strong inhibition effect on growth and biomass accumulation. Al and A3presented a promotion effect.40to80days after planting, Soak liquid treatments inhibited height, leaf growth and biomass accumulation. Such effect continued to increase as the treatment duration and mass concentration increased. In addition, leaf litter treatment presented a stronger inhibition effect than soak liquid treatment within the entire experiment.In each stage, all leaf litter treatments significantly inhibited the chlorophyll and carotenoid accumulation (P<0.05) which amplified as the amount of litter increased. The inhibition effect of soak liquid treatments mainly emerged at40d after planting and it increased as the liquid mass concentration increased while presents slight inhibition at20d and80d. Soak liquid treatment at80d were measured. And results showed:Leaf Pn, Tr, WUE, AQY, Lsp, Rd, Csp and CE were significantly lower than CK. Lcp and Ccp were higher than CK. However, under soak liquid treatment, stomatal conductance and intercellular CO2concentration were slightly higher than CK and stomata limitation was lower than CK which indicated that the effect of leaf litter soak liquid treatment on PE was slightly related with stomata while closely related with photosynthesis activity of leaf cell.In the entire experiment, Leaf POD presented no strong response in all treatments. But SOD and CAT presented strong response towards litter and soak treatments which were:at40d, SOD activity significantly higher than CK while CAT activity decreased sharply and was significantly lower that CK. At20d and80d, litter and soak treatments on SOD and CAT activity presented slight inhibition or promotion effect. The effect of litter on MDA was:at40d and80d after planting, MDA content of three litter treatments was significantly higher than CK and increased as the amount of litter increased. MDA content at20d insignificantly differed from CK. MDA content of soak liquid treatment had no significant difference with CK during the entire experiment.Three litter treatments inhibited the leaf proline and soluble protein accumulation in the entire experiment (Slight inhibition effect was detected at40d), but the soluble sugar accumulation was promoted (Slight promotion effect was detected at80d). Soak liquid treatment had very slight effects on the accumulation of proline, soluble protein and soluble sugar and even an inhibition effect was detected once in a while.To sum up, The Allelochemicals have inhibition with Brassica chinensis on both Eucalyptus grandis decomposition treatment and soak liquid treatment, and the inhibition by Eucalyptus grandis decomposition treatment is stronger than soak liquid treatment. |
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