Effects Of Soil Conditions On Growth And Physiological Characteristics Of Qing-nai

Qing-nai is a variety from Nai-li （Prunus salicina Lindl. var. cordata J. Y. Zhang et al）,which is native to Fujian China and should be studied systematically after introduced toTianjin. Qing-nai plants were cultivated in sandy and clay loam separately, aiming atunderstanding the effects of soil conditions on growth and development of Qing-nai, learningits adaptability to different soil in Tianjn city, exploring the possibility of planting Qing-nai inmild saline soils and providing the data for planting Qing-nai in a large scale in Tianjin aswell as the area with similar soil conditions as Tianjin. Meanwhile morphological andphysiological properties of Qing-nai and its mutant plants in the sandy soil were compared inthe experiment.The plots physical and chemical properties, including hydrolysable nitrogen, availablepotassium and phosphorus and organic matter contents, soil pH value and bulk density ofsandy and clay loam, were determined. Determinations of morphological and physiologicalcharacters of Qing-nai planted in two plots were conducted at the same time with soil examine.Plant morphological characters examined included single leaf area, trunk diameter, shootgrowth increment，shoot diameter and the largest shoot growth increment. Physiological andbiochemical properties determined included MDA, Pro and soluble sugar contents and PODand SOD activity as well as root dynamics. In addition, photosynthesis characters such as netphotosynthetic rate, stomata conductance, intercellular CO₂concentration and transpirationrate were studied.According to analyzing and comparing of the soil physical and chemical properties of thetwo plots, the morphological, physiological and biochemical characteristics andphotosynthesis of Qing-nai and its mutation planted in sandy soil the results were summarizedbriefly as follows:1、Soil compaction of both two plots were relatively great, though there was differencebetween the two plots in the soil texture （the plot in East Campus is clay loam, while that ofWest Campus is sandy soil）. Bulk density of the clay loam was higher than that of the sandysoil. Besides of available P, organic matter, hydrolysable nitrogen and available K in the clay loam were higher than that in the sandy soil. The two plots was alkaline soil, with strongeralkalinity in clay loam. Based on the data analyzed both two plots should be considered aspoor nutrient soils. Salt content in the two plots was middle or low and should not be therestrictions for the growth of Qing-nai.2、The single leaf area, trunk diameter, shoot growth increment, shoot diameter andsingle largest shoot growth increment of Qing-nai planted in the sandy soil was verysignificantly higher than those in the clay soil. The activity of underground fibrous root ofQing-nai planted in the sandy soil is higher than those in the clay soil. There was nosignificant difference between activities of the root with2mm diameters sampled from clayand sandy soils separately. It was known from the analysis of indexes quoted above and thefield observations that the plants in the sandy soil grew more vigorously than the plants in theclay soil.3、MDA and soluble sugar contents and activity of POD of Qing-nai cultivated in theclay loam was very significantly higher than that in the sandy loam, and activity of SOD fromthe clay loam was significantly higher than that from the sandy loam. There was nosignificant difference between the two plots in respect of Pro content. The results suggestedthat protective enzyme activity and intracellular contents of Qing-nai trended to increase orbecame higher when the plants were cultivated under soil stress （high bulk density and pHvalue and moderate salt content）.4、The diurnal variation of net photosynthetic rate of both two plot plants presented abimodal curve. The net photosynthetic rate of Qing-nai plants which planted in the sandy soilwas higher all the time. The net photosynthetic rate of both two plot plants presented a lowvalley at pm1:00, proposing that there was obvious photosynthetic midday depression. At thesame concentration of CO₂, the net photosynthetic rate of Qing-nai planted in the sandy soil ishigher than those in the clay soil. With the increasing concentration of CO₂, the netphotosynthetic rate of both two plots increased at the beginning and decreased afterwards. Inthe sandy soil, Qing-nai plants could keep increasing the net photosynthetic rate in the largerrange of CO₂concentration, expressing a higher productivity.5、Comparing the common Qing-nai with its mutant plants, it was found that the mutantplants performed some different characters from the common Qing-nai, such as thicker shoot,shorter internodes, earlier flower bud sprout in spring, natural leaves fall in autumn and higher net photosynthetic rate, but there was no significant difference between the two kindsplants in MDA, soluble sugar and Pro contents and activities of POD and SOD. In the future,the fruit traits should be analyzed to make further identification and evaluation for themutants.A suggestion could be drown from Qing-nai indexes examined in the experiment and itsfield observation that Qing-nai should be planted in loose, good ventilation, proper soil pHconditions, especially avoiding cultivation in heavy clay soil as long as chance of soilselection exists.