【摘要】：海南憑借得天獨厚的生態(tài)環(huán)境和氣候優(yōu)勢,成為全國重要的冬季瓜菜生產(chǎn)基地,常年大棚瓜菜種植面積約1.2萬公頃。�？诙疽资軓�(qiáng)冷空氣影響,形成低溫寡照天氣,對瓜菜生長發(fā)育不利,己成為大棚瓜菜栽培的主要氣象災(zāi)害。構(gòu)建適用于大棚瓜菜生產(chǎn)的低溫寡照災(zāi)害等級指標(biāo),為政府機(jī)關(guān)、農(nóng)業(yè)部門、大棚種植戶快速掌握災(zāi)情信息,制定適當(dāng)減災(zāi)防災(zāi)措施,最大限度減少氣象災(zāi)害造成的傷害和損失,為海南冬季反季節(jié)大棚瓜菜的安全高效生產(chǎn)提供有利保障。 本文采用室內(nèi)試驗和田間試驗相結(jié)合的方法,構(gòu)建了大棚西瓜整個生育期低溫寡照氣象災(zāi)害等級指標(biāo)。室內(nèi)試驗研究了低溫弱光對西瓜幼苗生理生化和形態(tài)的影響,并對西瓜幼苗受害進(jìn)行等級劃分。田間試驗利用歷史年份氣象數(shù)據(jù)統(tǒng)計出綜合氣候指數(shù)(HI),將調(diào)查年份低溫寡照綜合指數(shù)與西瓜受損情況結(jié)合構(gòu)建西瓜低溫寡照災(zāi)害等級指標(biāo)。將觀測站與大棚建立氣象數(shù)據(jù)模型,得出適用于大棚西瓜栽培的災(zāi)害等級指標(biāo)體系,再利用歷史資料對指標(biāo)進(jìn)行驗證分析。本研究主要結(jié)論如下： (1)低溫弱光脅迫減緩了西瓜幼苗下胚軸、莖粗和葉面積的增長,抑制了葉片光合作用,并造成光合機(jī)構(gòu)的損害。低溫弱光誘導(dǎo)了SOD和POD活性增強(qiáng),對消除體內(nèi)過多活性氧自由基有積極作用,而隨著低溫弱光脅迫的持續(xù),抗氧化酶合成途徑受到抑制。低溫弱光導(dǎo)致了MDA含量的增加,造成細(xì)胞膜脂過氧化傷害。此外,適當(dāng)弱光促進(jìn)幼苗下胚軸和葉面積增長,并能減緩幼苗在低溫下所受傷害。 (2)基于對西瓜幼苗在低溫弱光下生理和形態(tài)變化規(guī)律及抗性機(jī)理的研究,將西瓜幼苗在晝夜溫度為15/10℃,光照強(qiáng)度為100μmol m-2s-1的低溫弱光脅迫處理6d以內(nèi)、6～12d、12d以上的受害程度劃分為輕、中、重三個等級。 (3)選取低溫寡照過程極端最低氣溫X1、≤15℃持續(xù)天數(shù)X2、有害積寒X3和寡照天數(shù)X4為主要致災(zāi)因子,利用1998～2008年歷史氣象資料統(tǒng)計出反映災(zāi)害強(qiáng)度的綜合氣候指數(shù)(HI),研究2012、2013年兩個冬季不同強(qiáng)度低溫寡照災(zāi)害下西瓜受害和減產(chǎn)情況,根據(jù)綜合指數(shù)HI值劃分低溫寡照災(zāi)害等級：0～5.3為輕度災(zāi)害,5.3～23為中度災(zāi)害,23以上為重度災(zāi)害。 (4)通過對氣象觀測站與試驗地塑料大棚建立日最低氣溫和有害積寒的關(guān)系模型,構(gòu)建出適用于塑料大棚西瓜栽培的低溫寡照災(zāi)害等級指標(biāo),其中,綜合指數(shù)HI在2-8為輕度災(zāi)害,8-32為中度災(zāi)害,32以上為重度災(zāi)害。此外,選取日最大溫差、日均氣溫與日照時數(shù)建立了回歸模型,實現(xiàn)了對未來天氣日照時數(shù)的預(yù)報。 (5)對歷史年份西瓜不同栽培方式的低溫寡照災(zāi)害分析表明,相比于露地栽培,通過搭建塑料大棚在對低溫寡照氣象災(zāi)害的抵御能力方面有一定程度提高,并能有效減輕西瓜遭遇不利天氣造成的傷害和損失。
[Abstract]:Hainan, with its unique ecological environment and climatic advantages, has become an important winter gourd and vegetable production base in China, with an area of about 12000 hectares planted in the greenhouse all year round. Haikou is easy to be affected by strong cold air in winter, forming low temperature and low light weather, which is unfavorable to the growth and development of melon and vegetable, and has become the main meteorological disaster in greenhouse. To construct the index of low temperature and low radiation disaster grade suitable for the production of greenhouse melon and vegetable, so as to quickly grasp the disaster information for government organs, agricultural departments and greenhouse growers, and formulate appropriate measures for disaster reduction and prevention. The damage and loss caused by meteorological disasters were minimized, which provided a favorable guarantee for the safe and efficient production of melon and vegetables in off-season greenhouse in Hainan Province. In this paper, the indexes of low temperature and low radiation meteorological disasters for the whole growing period of watermelon in greenhouse were established by the combination of laboratory experiment and field experiment. The effects of low temperature and low light on physiology, biochemistry and morphology of watermelon seedlings were studied in laboratory. Based on the meteorological data of historical years, the comprehensive climate index (HI),) was used to construct the damage index of watermelon by combining the comprehensive index of low temperature and low light with the damage of watermelon. The meteorological data model of observation station and greenhouse was established, and the disaster grade index system suitable for watermelon cultivation in greenhouse was obtained, and the index was verified and analyzed with historical data. The main conclusions were as follows: (1) low temperature and low light stress slowed the growth of Hypocotyl, stem diameter and leaf area, inhibited leaf photosynthesis, and caused damage to photosynthesis. The activity of SOD and POD was enhanced by low temperature and low light, and it had a positive effect on eliminating excessive active oxygen free radicals. However, with the persistence of low temperature and low light stress, the synthesis of antioxidant enzymes was inhibited. Low temperature and low light resulted in the increase of MDA content and the damage of lipid peroxidation. In addition, proper low light could promote the growth of hypocotyls and leaf areas, and slow down the damage to watermelon seedlings under low temperature. (2) based on the study of physiological and morphological changes and resistance mechanism of watermelon seedlings under low temperature and low light, The damage degree of watermelon seedlings under low temperature and low light stress (temperature 15 / 10 鈩，

本文編號：2141325