低温寡照对设施番茄的致灾机理及灾损评估模型研究

Tomato is the most predominant greenhouse crop in China. Low temperature and scant light always occur simultaneously, which results in composite meteorological disaster in the production of greenhouse tomato. The area of greenhouse tomato suffered from low temperature and scant light accounts for 20% of the total area of greenhouse tomato. The biological mechanism that low temperature and scant light caused the arrest of growth and development, the decline of yield and quality of greenhouse tomato is still not clear. Disaster damage assessment model based on the disaster-causing mechanism has not been established and applied. A controlled environment experiment is designed in this research to simulate the weather patterns of low temperature and scant light composite meteorological disaster. Tomato (Solanum lycopersicum.cv. Jinfen 5) plants will be treated in low temperature and scant light environment with different stress intensity and duration, and all of the plants will then be transferred to a suitable environment. The biological mechanism of low temperature and scant light disaster, as well as the repair characteristics of tomato plants that suffered from the composite meteorological disaster will be studied by measuring the cell membrane permeability and protective enzyme activity of leaf tissue, the photosynthetic characteristics and chlorophyll fluorescence parameters of leaf and the contents of endogenous hormone and nutrient substance in organs of tomato plants. Meteorological disaster indexes and parameters for models can be obtained through the measurements of canopy structure, yield and quality of fruits. Meanwhile a greenhouse microclimate forecasting model will be developed using the meteorological data inside and outside the greenhouse. Based on the above work the greenhouse tomato growth and development model that has been established by our group will be enhanced to develop a new model to assess the damage of low temperature and scant light on growth, development, yield and quality of greenhouse tomato. The research aims to provide support for assessment of low temperature and scant light meteorological disaster in greenhouse tomato.

番茄是中国最主要的设施作物。在设施番茄生产中，寡照常伴随低温构成复合气象灾害，每年遭受低温寡照危害的设施番茄面积占总面积的20%左右。目前，低温寡照致使设施番茄生长发育停滞、品质和产量下降的生物学机理及其如何灾损评估等科学问题尚不清楚。为此，本研究以番茄'金粉5号'为试材，利用环境控制试验模拟低温寡照发生的气候模式，同时开展设施栽培试验，设计不同低温寡照强度和持续时间及适宜气象条件下的恢复处理，通过测定叶片组织的细胞膜透性和保护酶活性、叶片光合特性和荧光参数、器官内源激素及营养物质，研究低温寡照致灾的生物学机制和受害植株的修复特性；再通过测定冠层结构、果实品质和产量，提取气象灾害指标和建模参数；同时利用设施内外气象数据构建室内小气候预报模型；在此基础上，对项目组已研制的作物模型改进，构建低温寡照对设施番茄生长发育和产量影响的灾损评估模型。研究旨为设施番茄低温寡照复合灾害定量评估提供支持。

番茄（Solanum lycopersicum）是中国主要设施栽培作物，在冬春生产季节，寡照灾害常导致低温同时发生而形成复合气象灾害，对设施番茄植株产生严重危害。因而低温寡照对设施番茄的致灾机理、灾后植株的恢复特性以及如何评估低温寡照的影响一直是应用气象领域亟待解决的科学问题。 利用人工环境控制试验，昼温/夜温分别设置18/8°C、16/6°C、14/4°C、12/2°C 4个水平、光合有效辐射设置400μmol·m-2·s-1、200μmol·m-2·s-1 2个水平，以昼温/夜温28/18°C，PAR 800μmol·m-2·s-1，为对照，研究表明：随着低温寡照严重程度的升高、处理时间延长，设施番茄叶片的净光合速率（Pn）、最大光合速率（Pmax）、光系统Ⅱ最大量子效率（Fv/Fm）、玉米素（ZT）、引哚乙酸（IAA）、赤霉素（GA3）均不同程度地呈现出下降的趋势，而光补偿点（LCP）、非化学淬灭系数（qN）、过氧化物酶(POD)和过氧化氢酶(CAT)活性、丙二醛(MDA)含量、脱落酸（ABA）、以及相对电导率则呈现出上升的趋势；低温寡照越严重，处理时间越长，番茄植株恢复到与CK相当的水平所需要的时间越长，其中经过低温寡照处理8d和10d的昼温/夜温12/2°C，PAR 400μmol·m-2·s-1和200μmol·m-2·s-1的处理在恢复21天后的番茄植株未能恢复到与CK相当的水平；低温寡照胁迫使番茄植株进入开花期、坐果期和红熟期时间延迟，且生育期推迟时间与低温寡照胁迫持续时间呈正相关；低温寡照胁迫会抑制番茄的开花，使番茄开花速度明显减慢，但胁迫时间不超过4d时植株不仅能恢复至CK水平，还能在一定程度上促进开花，当胁迫时间超过6d，会延迟植株开花，减小开花数，降低花粉活力，出现落花；低温寡照胁迫后番茄各形态指标均呈“S”型增长，并较CK均有不同程度减小；低温寡照复合胁迫严重影响番茄植株单株干物质生产，各处理结束后番茄植株干物质累积量随生长时间增加而增加但显著低于CK。低温寡照处理4d以上番茄植株的坐果期明显延迟；低温寡照处理后番茄果实有机酸含量明显升高，并随胁迫程度的加剧而增加。番茄维生素C、可溶性固形物及番茄红素含量则在低温寡照胁迫后有所下降；利用室内外观测数据构建了设施小气候预报模型和基于温光效应的作物生长模型，最后构建设施番茄低温寡照灾损评估模型。