| Mulberry is planted in a large area in Heilongjiang province, it plays a more important role in revegetation of vulnerable ecological areas and to develop agroforesty, especially aroforesy in mulberry and soybean leguminous crops. The investigation was conducted by intercropping mulberry/soybean intercropping system and mulberry/alfalfa intercropping system, to study growth characteristics, soil nutrients content and soil enzyme activity in rhizosphere soil, land use efficiency and the photosynthesis characteristics of mulberry, soybean and alfalfa in mulberry/alfalfa intercropping system, and the effect of phenolic acids in soybean root exudate on the growth of mulberry. The study can provide theoretical basis for optimum model of mulberry/soybean intercropping and mulberry/alfalfa intercropping. The results are as follows:The results showed that plant height, content of chlorophyll, root dry weight,above-ground biomass of intercropped mulberry increased15.3%,21.6%,30.7%,43.3%,respectively, compared with sole mulberry during the co-growth stage in mulberry/soybean intercropping system, but reduced in intercropped soybean. Net photosynthetic rate (Pn),transpiration rate (Tr), stomatal conductance (Gs), intercellular CO2(Ci) of intercropped mulberry increased26.7%,100.3%,19.4%respectively, compared with sole mulberry,and water use efficiency(WUE) of intercropped mulberry decreased,37.2%, compared with sole mulberry,but increased in intercropped soybean. Mulberry and soybean intercropping enhanced light saturated point (LSP), light compensation points (LCP) and photosynthetic rate at light saturation (Pmax) of intercropped mulberry,and mulberry and soybean intercropping reduced light saturated point (LSP), light compensation points (LCP) and photosynthetic rate at light saturation (Pmax) of intercropped soybean,but mulberry and soybean intercropping enhanced apparent quantum yield (AQY) of mulberry and soybean.it indicated that mulberry and soybean intercropping enhanced the utilization efficiency of strong light by mulberry and that of weak light by soybean, and accordingly,the growth of mulberry and soybean was affected.In order to improve the yield of forage grass in songnen plain pastoral areas, an experiment was conducted by intercropping mulberry (Morus alba L.) and alfalfa (Medicago sativa L.) to study growth characteristics, soil nutrients content and soil enzyme activity in rhizosphere soil, land use efficiency and the photosynthesis characteristics of mulberry and alfalfa in mulberry/alfalfa intercropping system. The results showed that when the second cutting, plant height, leaf biomass, stem biomass, and crude protein content of intercropped mulberry was increased by9.2%,36.4%,46.5%and12.7%, respectively, as compared with mono-cropping mulberry; plant height, number of branches, content of chlorophyll a, content of chlorophyll b, and crude protein content of intercropped alfalfa was increased by8.7%,26.7%,11.4%,20.5%and21.4%, respectively, as compared with mono-cropping alfalfa. Organic nitrogen content,available nitrogen content, urease activity of intercropped mulberry in rhizosphere soil was increased by3.3%,19.1%,32.7%, respectively, as compared with mono-cropping mulberry; organic nitrogen content,available nitrogen content, urease activity of intercropped alfalfa in rhizosphere soil was increased by3.4%,27.9%,32.3%, respectively, as compared with mono-cropping alfalfa. The land equivalent ratio of mulberry/alfalfa intercropping system was1.29, land utilization ratio had been enhanced. Light saturated point (LSP), light compensation points (LCP) and photosynthetic rate at light saturation (Pmax) of intercropped mulberry was increased significantly by15.0%,39.3%, and20.7%, respectively, as compared with mono-cropping mulberry; reduced light saturated point (LSP), light compensation points (LCP) and photosynthetic rate at light saturation (Pmax) of intercropped alfalfa was reduced by15.6%,33.9%, and17.6%, respectively, as compared with mono-cropping alfalfa. Mulberry/alfalfa intercropping enhanced apparent quantum yield (AQY) of mulberry and alfalfa. It indicated that mulberry/alfalfa intercropping enhanced the utilization efficiency of strong light by mulberry and that of weak light by alfalfa, and accordingly, making mulberry/alfalfa intercropping system present an obvious yield advantage.In order to research the effect of phenolic acids in soybean root exudate on the growth of mulberry. In this paper, effects of3-nitro-phthalic acid,2-methoxy-benzoic acid on growth and photosynthesis characteristics of one year Qinglong mulberry seedlings were studied by pot experiment. The results showed that effects were different among two exogenous phenolic acids..When the concentration of exogenous3-nitro-phthalic acid was lower than10-5mol·L-1, the content of chlorophyll of mulberry leaves, net photosynthetic rate (Pn),transpiration rate (Tr), stomatal conductance (Gs), intercellular CO2(Ci), assimilate accumulation increased with increasing of the concentrations of3-nitro-phthalic acid and suggested promotion of growth of the plant height, root length and biomass. When the concentration of exogenous3-nitro-phthalic acid was higherer than10-2mol·L-1, the content of chlorophyll of mulberry leaves, Pn, Ci and ETR, ΦPSⅡ were decreased significantly, the plant height, root length, leaf number and biomass of mulberry were also decreased. The content of chlorophyll of mulberry leaves, Gs, Tr, Pn, ΦPSⅡ, ETR and photochemical quenching (qp) and the rate of energy dissipation were increased with increasing of the concentrations of exogenous2-methoxy-benzoic acid. Our study indicated that3-nitro-phthalic acid had dual effects on growth and photosynthesis characteristics of mulberry seedlings:low concentrations of3-nitro-phthalic acid may stimulate and high concentrations may inhibit growth of mulberry seedlings.2-methoxy-benzoic acid had adverse effects on the leaf photosynthetic system of mulberry seedlings... |
PDF Full Text Request