| A study on environmefltal factors and plam transpiration in solar greenhouseunder drip irrigation is the basis of determining a greenhouse environrnentalmanagement system and scieIltific irrigation schedule. At the same time, it is alsoimportant to perfect the technique systCm of greenhouse crop cultivation and promotethe development of protected agriculta furtheL In this exPeriment, a saP flow gaugeand an aotomatic weather station were used to investigatC the variations ofenvironmental factors and plat transpiration in solar greenhouse under dripirrigation.The main conclusions achieved by analyzing the data from monitoringenvironmental factors are as follows'l. There was a bigger variation in radian intensity above canopy from south tonorth than that from east to weSt, bllt the measuremefit results under canopy wereopPosite. Generally speaking, the differences of radiant intensity from top to bottomwere greater than those from soulh to north.2. In wintef, the air temperatures increased gradually frOm south to north at night.The highest air temperature aPpeared at the middle-sollthem part in greenhouse indaytime. In vertical direction, the air temPeratures nearby plam canopy were lowerand increased with height above canopy.3. The soil temperatures increased gradually from sollth to north. In the west-eastem direction, soil temPeratures in west in the morning were higher than that ineast, bot the resu1t was opposite in the aftemoon.4. The correlation between the radian intensity and atmospheric humidity in finedays was higher than that in cloudy days. The correlation coefficients in fine andcloudy days were -0. 79 and -0. 59 respectively.The variations of physiological and ecological indexes such as the plan sap floWstomatal conductance, celluIar liquid concendation, canopy tCmPerature and thecanopy-air temPerature differences were stUdied and analyzed. The main results are asfollows:1. In fine days, the daily sap flow changed obviously as a single-apex curve. No matter what kind of the weather, the plant sap flow varied with solar radiation. In general, the plant sap flow velocity of the high-moisture treatment was higher than that of the low-moisture treatment, and the differences of sap flow between treatments were obvious at noon. As for the same plant, the sap flow of trunk was larger than that of branches and their variations were similar. After some leaves on a plant were removed, the sap flow velocity reduced considerably compared with the normal plant, but their daily variations were in the same patterns,2. The stomatal conductance had a great difference in different positions of the leaf and among the leaves of the plant. The effects of environmental factors on stomatal conductance were analyzed and the model about stomatal conductance and environmental factors was established. The regression equation between the stomatal conductance and plant transpiration was established and the coefficient of correlation was 0.9.3. The cellular liquid concentration differed among the leaves of the plant. The results showed that the cellular liquid concentration of the top leaf and the bottom leaf was smaller. However, the cellular liquid concentration of the third and the fourth leaf from top to bottom was higher. The cellular liquid concentration in low-moisture treatment is higher than that in high-moisture treatment, which differed clearly at noon.4. The canopy temperature was close related to soil water content. It was larger in low-moisture treatment than in high-moisture treatment and the differences of canopy temperature between treatments were obvious at noon. The correlation analysis indicated that the canopy-air differences at 11:00 or 12:00 could reflect commendably the status of soil water. The correlation coefficients between canopy-air differences, VPD, atmospheric humidity, air temperature and radiant intensity were- 0. 65, 0. 58, -0. 53, -0. 35, respectively. But, the correlation between the plant trans...
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