Effects Of Physicochemical Properties And Bacterial Diversity Of Peat-moss On Growth Of Cucumber And Tomato Plug Seedlings

The physicochemical properties and bacterial diversity variation of peat-moss from different areaswas firstly studied. And then the mineral nutrients and bacterial diversity changes in cucumber(Cucumis sativus L.)and tomato(Lycopersicum esculentum Mill)seedling rhizosphere, cultivated indifferent substrates were researched.1. Four commercial substrates were collected and their physicochemical properties andapplication effects on the cucumber and tomato seedlings was analyzed. The results indicated thatproportion the particle size of1-0.5mm was more than33%. The total porosity, aeration porosity,water-holding porosity were close and the difference was less than10%. Total N, P, K and available N, P,K contents of Luqing, Jinse No.1and Jinse No.3were higher than Sunshine mix. The ash content andwater absorption capacity of Sunshine mix were higher than other substrates. Height, stem diameter,seedling index, the first true leaf area, fresh and dry weight of cucumber and tomato seedlings werehighest in Luqing. Chlorophyll conent of cucumber seedling was highest in Jinse No.1, while thechlorophyll content of tomato seedling was highest in Jinse No.3. Root shoot ratios of cucumber andtomato seedlings were highest in Sunshine mix.2. The physiochemical properties of peat-moss from overseas and domestic were analyzed andsome remarkable differences were found between four overseas peat-moss and four domesticpeat-moss．The results indicated that the decomposition degree of domestic peat-moss was much higherthan that of the overseas peat-moss．Therefore, the ratio of＜0.5mm particle of was greater,about4-10folds over the overseas peat-moss．Also, the saturation moisture content of the domesticswas lower, only50%of the values obtained from the overseas peat-moss． Furthermore, wedemonstrated that compared to the overseas, the domestic peat-moss contained higher contents of totalN, P and K, available N, but lower content of available P and K.3. The bacterial diversity of eight peat-moss and the substrates fromed by them for tomatoseedlings was studied with PCR-DGGE method. The Shannon-wiener of Qingyuan was highest, that ofKlasmann was lowest. The number of bands in Liaoyuan, Huachuan and Yanshou was24, highestamong them. The number of bands in Pindstrup was lowest and was19. Furthermore, the evennessindex of Yanshou was highest, Kekkila was lowest. The highest coefficient of community similarityamong the groups was72.9%, found between Huachuan and Yanshou, while the lowest was55.6%,found between Kekkila and Huachuan.20and30days after seeding, the bacterial diversity, richness,evenness index in tomato seedlings rhizosphere cultivated in eight substrates rised. Otherwise, with thegrowth and development of tomato seedlings, the similarity coefficient among the rhizosphere bacterialDGGE profiles in eight substrates rised.4. The substrates formed by peat-moss of Panda and Klasmann were used to cultivate thecucumber and tomato seedlings. With the growth and development, total N, P, K, Ca, Mg and availableN, P, K, Ca, Mg content in rhizosphere of cucumber and tomato seedlings decreased, but the changes of the total K, Mg, pH and Eh in the cucumber seedlings rhizosphere between the two substrates werevaried, and the total K, total Ca and Eh in the tomato seelings rhizosphere between the two substrateswere different.