不同生育阶段土壤含水率对番茄果实维生素C含量的影响

Effect of Soil Water Content at Different Growth Stages on Vitamin C Content in Tomato Fruit

为实现番茄的优质生产及水资源高效利用,探求不同生育阶段土壤含水率与番茄果实维生素C含量之间的关系。以番茄苗期、始花结果期、果实生长初期、膨大期和品质形成期5个阶段的土壤含水率为试验因素,每个因素设5个水平,采取五元二次通用旋转组合设计,进行盆栽试验。建立维生素C含量与不同阶段土壤含水率的数学模型,分析因子主效应、单因子效应及两因素的耦合效应,并对模型模拟寻优。结果表明,品质形成期土壤含水率对番茄果实维生素C含量的影响最大,苗期次之,始花结果期最小。控制其它阶段土壤水分为（70%~80%）θf时,果实维生素C含量随苗期、始花结果期土壤含水率变化不大（变异系数分别为2.46%、3.08%）;随果实生长初期、膨大期和品质形成期土壤含水率呈抛物线变化,且影响程度依次增大（变异系数分别为5.79%、8.09%、17.25%）,且这3个阶段土壤含水率分别为（67.79%~77.79%）θf、（65.58%~75.58%）θf、（68.86%~78.86%）θf时,维生素C含量有最大值,分别为24.10、24.21、24.10 mg/（100 g）。耦合效应表明,苗期与始花结果期和果实生长初期、始花结果期与膨大期、膨大期与品质形成期土壤含水率对番茄果实维生素C含量的交互作用均呈正效应;苗期与膨大期和品质形成期、始花结果期与果实生长初期和品质形成期、果实生长初期与膨大期和品质形成期土壤含水率间的交互作用均呈负效应。在5个阶段土壤含水率分别为（50%~60%）θf、（90%~100%）θf、（50%~60%）θf、（80%~90%）θf、（70%~80%）θf时,番茄果实维生素C含量达最高30.10 mg/（100 g）,但不利于产量的形成。当5个阶段土壤含水率分别为（90%~99.9%）θf、（90%~99.8%）θf、（90%~99.6%）θf、（74.0%~81.8%）θf、（74.3%~82.5%）θf时,可以同时获得较高的番茄单株产量（996.75~1 037.99 g）和维生素C含量（25.40~26.02 mg/（100 g））。

Pot experiment was conducted to determine the response of vitamin C（ VC） content in tomato fruit to soil water condition at different growth stages. Growth stages were divided by the law of tomato development and the growth of the first cluster fruits,including seeding,flowering,fruit early growing,inflation and quality formation stages. Five levels of soil water condition were set at each stage,and quadratic general composite rotatable method with five factors was used. Mathematical model between VC content and soil water content of different stages was established. The main effect,single effect andcoupling effect of two factors were analyzed,and model optimization was operated in DPS 3. 0. Results showed that the influence of soil water content at quality formation stage on VC content was top-drawer,seeding stage was ranked the second and flowering stage was taken the least. When other stages＇ soil water content was（ 70% ~ 80%） θf,with the increase of soil water content at seeding or flowering stages,VC content in tomato fruit was varied slightly（ variable coefficients were 2. 46% and 3. 08%,respectively）,while a downwards parabola change was found when soil water content was risen at other three stages. Additionally,the peaks of parabola were 24. 10 mg /（ 100 g）,24. 21 mg /（ 100 g） and24. 10 mg /（ 100 g） when soil water contents were（ 67. 79% ~ 77. 79%） θf,（ 65. 58% ~ 75. 58%） θfand（ 68. 86% ~ 78. 86%） θf,respectively. There were significant coupling effects of two factors on tomato VC content,both positive and negative. VC content might reach the highest level of 30. 10 mg /（ 100 g）when soil water content at five different stages were（ 50% ~ 60%） θf,（ 90% ~ 100%） θf,（ 50% ~60%） θf,（ 80% ~ 90%） θfand（ 70% ~ 80%） θf,respectively,while yield was decreased sharply.Tomato yield and VC content in fruit acquired desirable level,which were 996. 75 ~ 1 037. 99 g / plant and25. 40 ~ 26. 02 mg /（ 100 g） when soil water contents at five stages were（ 90% ~ 99. 9%） θf,（ 90% ~99. 8%） θf,（ 90% ~ 99. 6%） θf,（ 74. 0% ~ 81. 8%） θfand（ 74. 3% ~ 82. 5%） θf,respectively.