【作者】 和红云；

【导师】 薛琳； 田丽萍；

【作者基本信息】 石河子大学 ， 蔬菜学， 2008， 硕士

【摘要】 本研究以新疆两个甜瓜主栽品种早金和伊丽莎白为试验材料,利用人工气候箱(RXZ型,宁波江南仪器制造厂制造)进行控温的办法,研究了三个温度条件下(30℃/20℃(昼/夜,下同)、21℃/12℃、15℃/7℃)对两种甜瓜幼苗生长和生理生化特性的影响,以期揭示不同甜瓜品种间生理生态的差异,为选育耐低温品种及鉴定方法提供理论依据。主要试验结果如下:1. 15℃/7℃下,甜瓜幼苗的生长受到抑制,幼苗高度、株叶面积、干物质积累量增加缓慢,叶绿素含量随低温持续时间的延长而下降;15℃/7℃下处理10d时,早金幼苗叶片严重失绿、黄化,生长点枯黄,个别植株死亡;伊丽莎白幼苗叶片症状较轻;21℃/12℃对甜瓜幼苗的生长抑制小于15℃/7℃,该温度对早金的生长抑制较对伊丽莎白的抑制重;30℃/20℃条件造成早金幼苗新生叶叶片薄而小、叶柄和节间长,而伊丽莎白幼苗生长基本没有影响。低温对早金幼苗的生长抑制作用强于其对伊丽莎白。2.两个品种在各温度下幼苗根系活力随时间延长呈先升后降的趋势。脯氨酸、可溶性蛋白含量和可溶性糖的变化趋势是随着温度梯度的下降而升高,并且随着持续时间的延长现下降后上升。15℃/7℃条件下,脯氨酸和可溶性糖都明显高于30℃/20℃、21℃/12℃条件。对比两个品种间的数据可以得出伊丽莎白的各项指标高于早金,证明了伊丽莎白对低温胁迫有更强的耐受性。3.与30℃/20℃条件相比,21℃/12℃和15℃/7℃条件造成了两个甜瓜品种幼苗光补偿点、CO2补偿点升高,光饱和点、CO2饱和点降低,说明低温条件降低了甜瓜幼苗叶片光合能力和CO2利用范围;两个品种叶片在15℃/7℃下的气孔导度、蒸腾速率、气孔限制值、水分利用效率、瞬时光合效率比20℃/12℃、30℃/20℃显著下降,但细胞间隙CO2升高,表明低温胁迫下甜瓜幼苗净光合速率下降的原因以非气孔限制因素为主。低温下Fv/Fm及Fv/Fo均显著降低,反映了低温胁迫使甜瓜叶光系统Ⅱ(PSⅡ)活性中心受损;低温胁迫也影响了甜瓜幼苗的qP和qN,表现为qP的下降和qN的升高。qP的降低说明QA重新氧化能力减弱,PSⅡ的电子传递活性下降;qN的升高说明甜瓜幼苗通过耗散多余能量以保护光合机构免受低温伤害的能力增强。4.细胞膜透性、MDA含量以及SOD、POD、CAT活性可以作为甜瓜幼苗低温耐受性鉴定依据。低温胁迫使甜瓜幼苗的细胞膜相对透性增大,MDA含量升高,在15℃/7℃条件下随时间延长有明显的增加趋势。在处理时间内,随着温度降低和持续时间延长,两个品种SOD活性呈现先升后降的趋势,POD活性呈现升高的趋势,而CAT则相反呈现下降趋势。各温度条件下,伊丽莎白细胞膜透性、MDA含量以及SOD、POD、CAT活性均低于早金。5.伊丽莎白忍耐低温、适应低温的能力强于早金,可以作为设施冬春季甜瓜栽培的适宜品种之一。综上所述,低温对甜瓜幼苗的生长和生理活动影响极大,本研究证实,15℃/7℃条件及持续时间较长的21℃/12℃条件均会影响甜瓜的生长。反季节生产中应该以选择耐低温品种为前提制定技术方案,在生产过程中遭遇低温时,应注意利用设施所具有的可控、可调的性能给予保温增温。更多还原

【Abstract】 Muskmelon planting is a developing style in greenhouse for these years, which represents an important effect on innovating agricultural structure and improving rural economy in Xinjiang of China. Hence, it is indispensable to frame technique project of melon planting that researching how the chilling influence growth of muskmelon and how muskmelon respond to chilling in order to acclimatize itself to it. Zaojin and Elizabeth, Muskmelon seedlings(Cucumismelo L)of two cultivars of Xinjiang’s leading planting as material were treated under different low-temperatures (30℃/20℃、21℃/12℃、15℃/7℃,d/n) in this study to research seedlings growth and on physiological & biochemical properties in seedlings leaves. The results weresummarized as following:1. Low temperature can inhibit height, the area of total leaves, fresh weight of the part above & under the ground, R/T, root vigor and dry weight accumulation of Muskmelon seedlings, the inhibitions of 15℃/7℃areserious than those under the other temperatures. Though height, the area of total leaves, fresh weight of the part above & under the ground of Elizabeth seedlings are lower than Zaojin seedlings, the R/T ratio, root activity and dry weight accumulation of Elizabeth are higher than Zaojin. It suggested that Elizabeth has stronger endurance to low temperature than Zaojin.2. The root activities of both cultivars increased at first and then decreased under any temperature. Praline, soluble sugar and soluble protein increased with the temperature decreased. The condition of 15℃/7℃, praline and soluble sugar were obviously higher than other condition of 30℃/20℃and 21℃/12℃. From the result of copare with two cultivars’date , we may discern all indexes of Elizabeth was higher than Zaojin.The results demonstrated Elizabeth have more harier than Zaojin.3. Under low-temperature(15℃/7℃) the net photosynthetic rate (Pn),evaporation rate (Evap.), stomatal conductance (Gs),and chlorophyll fluorescence kinetics parameters such as Fm, Fv, Fv/Fm , Fv/Fo,FPSⅡof leaves decreased, while the thermal energy dissipation rate and photosynthetic limitation increased. The intercellular CO2 concentration(Ci) was higher than it under the other two temperature. The cause of reduction of Pn in muskmelon seedling leaves under low-temperature might be mainly non-stomata limitation. The results also suggested that chloroplast were injured by 15℃/7℃in long-term treatment. Elizabeth has more stonger photosynthesis than Zaojin under low-temperature.4. It suggested that the membrane permeability, MDA and activity of SOD, CAT, POD can be used as target for identifying cold- tolerance cultivars. The membrane permeability and MDA increased in both culivars with the decrease of temperature . Under the condition of 15℃/7℃MDA was conspicuously high.With the temperature decreaded and the time prolonging , the activity of SOD and CAT were decreased, then POD activity was increased.All of every condition, the membrane permeability, MDA and activity of SOD, CAT, POD of Elizabeth were lower than Zaojin.5. Elizabeth has stronger ability to endure low temperature, which can be selected as one of the cultivars for muskmelon planting in greenhouse.In conclusion, low temperature would damage muskmelon seedlings. For anti-season planting in greenhouse, it is very important that establishing technique project of melon planting based on selecting chilling- tolerance cultivar. It is also very important that improving temperature to avoid chilling-damage occurrence on muskmelon seedlings.更多还原