To understand the effects of different moisture stress on sap flow and leaf potential of tomato in greenhouse, authors conducted the experiments under three water treatments, including normal water supply (T1 ) , light water stress treatment (T2) and severe water stress treatment ( T3 ) ,for tomato variety "Jingfen 2' . The results showed that the daily variation of sap flow of tomato plant occurred as a bimodal curve under Tl and T2 in sunny days, and the bottom point was at 12; 00 in the noon with the stoma closed. The sap flow of tomato changed slightly under Tl and T2 in cloudy days. The transpiration changed a lot under different water stresses. Transpiration became less with more serious water stress. The difference between different transpiration decreased gradually with time extension after irrigation, leaf water potential decreased was well, with T1 > T2 > T3. In addition, solar radiation, air temperature and relative air humidity (RH) was the main meteorological factors affecting sap flow rate of the tomato by correlative analysis. The results indicated that there was a positive correlation between the sap flow and solar radiation, air temperature and soil moisture. On the contrary, there was a negative correlation between the sap flow and leaf water potential and the relative air humidity (RH).%以番茄“金粉2号”(Jingfen 2)品种为试材,设正常灌溉(T1)、轻度胁迫(T2)和重度胁迫(T3)3个土壤水分处理,观测不同土壤水分条件下番茄植株的茎流速率和叶片水势.结果表明,番茄植株茎流速率日变化呈现明显的规律性,晴天,T1和T2的番茄茎流速率呈明显的双峰曲线,中午12:00左右气孔关闭,茎流速率出现低谷.阴天,T1和T2处理番茄茎流日变化趋势总体较为平缓.不同水分处理下番茄的蒸腾量差异明显,水分胁迫处理的番茄蒸腾量均小于正常灌溉,土壤水分胁迫程度越严重,日蒸腾量越低.随着水分处理天数的增加,不同灌溉处理番茄的蒸腾量差异逐渐缩小.叶片水势随灌溉后天数增加而逐渐减少,叶片水势T1＞T2＞T3.相关分析表明,影响番茄茎流的主要气象因子为太阳辐射、空气温度和空气湿度.研究认为,番茄茎流与太阳辐射、空气温度和土壤水分呈正相关,叶片水势与空气相对湿度呈负相关.研究结果可为设施番茄水分管理提供科学依据.
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