【作者】 吕杰；

【导师】 王秀峰；

【作者基本信息】 山东农业大学 ， 蔬菜学， 2007， 硕士

【摘要】 在温室、大棚等园艺设施作物栽培中,由于特殊的栽培环境,肥料不合理使用、栽培管理措施不当、地下水上升等因素致使土壤中盐分聚集,引起设施土壤次生盐渍化。而设施土壤盐分的组成特点为:阴离子以NO3-为主,阳离子则以Ca2+和K+为主。为此,本试验以黄瓜为材料,研究不同种类硝酸盐对黄瓜幼苗生理特性的影响,主要结果如下:1.高浓度的硝酸盐抑制黄瓜幼苗的生长,而不同种类的硝酸盐对黄瓜幼苗生理特性的影响差异较大。NaNO3处理条件下,随着NO3-浓度增加,黄瓜幼苗生物量降低、根系吸收能力及吸收面积下降;而低浓度Ca(NO3)2及KNO3处理下,黄瓜幼苗生物量随着NO3-浓度增加而增加,当大于98 mmol·L-1时,黄瓜幼苗鲜重逐渐降低。相同NO3-浓度条件下,Ca(NO3)2处理长势好于KNO3处理。2.硝酸盐胁迫下,黄瓜叶片中MDA含量、电解质相对渗漏率及保护酶活性均逐渐增加。不同硝酸盐处理下的黄瓜幼苗对其响应也有所不同。NO3-浓度小于98 mmol·L-1时,Ca(NO3)2处理的黄瓜幼苗中MDA含量和电解质相对渗漏率变化不明显,而NaNO3和KNO3处理的黄瓜幼苗中MDA含量和电解质相对渗漏率升高。与其它硝酸盐相比,NaNO3处理的黄瓜幼苗中保护酶活性较高。3.黄瓜幼苗的光合特性对不同种类硝酸盐的响应也有所不同。NO3-浓度为14~98 mmol·L-1时,Ca(NO3)2处理的黄瓜幼苗叶绿素含量逐渐增加,光合速率、蒸腾速率和气孔导度均逐渐升高,但处理浓度继续增加时,光合能力开始下降;KNO3处理的黄瓜幼苗光合参数变化不明显;NaNO3处理下,其光合参数则一直呈下降趋势。当KNO3和NaNO3的处理浓度分别高于140 mmol·L-1和98 mmol·L-1时,叶片发生萎蔫。高浓度的NaNO3和KNO3处理条件下,黄瓜幼苗光合能力的下降可能是受非气孔因素的影响。4.不同种类的硝酸盐对黄瓜幼苗矿质元素的吸收影响较大。随NO3-浓度的增加,Ca(NO3)2处理的黄瓜幼苗叶片和根系中P、Fe和K含量均呈先升高后降低趋势;而KNO3处理的黄瓜幼苗叶片和根系中的P和Ca含量亦呈先升高后降低趋势,NO3-浓度为98 mmol·L-1时达最大,而Fe的含量则逐渐下降;NaNO3所有处理浓度下黄瓜幼苗叶片和根系中P、K、Ca、Fe含量均低于对照。5.两种钠盐均抑制了黄瓜幼苗的生长,与NaCl处理相比,NaNO3处理下的黄瓜幼苗生物量、根系吸收能力及光合速率较低;而叶片和根系的渗透势、渗透调节物质含量、MDA含量、电解质相对渗漏率和保护酶活性较高;而NaNO3处理的黄瓜幼苗Na+含量明显高于NaCl处理。尽管NaCl处理的黄瓜幼苗长势相比NaNO3好,但较Ca(NO3)2和KNO3处理长势差。更多还原

【Abstract】 In the establishment cultivation such as greenhouse and shed of horticultural crops,because fertilizer was unreasonablely applied, culture management was unsuitable, and ground water rised, which caused soil secondly salinization. The main anion of facilities soil salt is NO3-, the main cation is Ca2+ and K+. Therefore, this experiment was desighed about the effect of different salt treatments on physiological and biochemical characteristics of cucumber seedlings.The main results were as follows:1. High cocentration nitrate inhibited the growth of cucumber seedlings. There were great differences in effect of different nitrates on cucumber seedlings. With the increasing of NO3- concentration, the biomass, root absorbability and root absorbing area declined under NaNO3 treatment. The biomass was gradually increased with NO3- concentration increasing under Ca(NO3)2 and KNO3 treatments, while NO3- concentration excessed 98 mmol·L-1, the fresh weight of cucumber seedlings was gradually decreased. Under the same NO3- concentration, the growth of cucumber seedlings under Ca(NO3)2 was better than under KNO3.2.Under nitrate stress, the MDA content, the relative electronic leakage and protective enzyme activity were gradually increased. There were different responses on cucumber seedlings under different nitrate treatments. While NO3- concentration was less than 98 mmol·L-1, there were no distinct changes in MDA content and electri conductivity by Ca(NO3)2. But the MDA content and the relative electronic leakage were increased under NaNO3 and KNO3. Compared with other nitrates, the protective enzyme activity ubder NaNO3 were higher .3.There were different responses on photosynthesis characteristic of cucumber seedlings under different nitrate treatments. The chlorophyll content, photosynthesis rate , transpiration rate and stomatal conductance rised gradually, increasing concentrations of NO3- from 14 to 98mmol·L-1, while increasing the concentration continuously, photosynthesis ability declined. There were no obvious changes on photosynthetic parameters under KNO3 treatment, photosynthetic parameters of cucumber seedlings leavese under NaNO3 descended gradually.Whlie NO3- concentration was more than 140and 98 mmol·L-1, the leaf was wilting. The decreasement of photosynthesis ability of cucumber seedlings leavese was caused by high concentration of NaNO3 and KNO3.4. There was great effect of different nitrate treatments on absorption of mineral elements. With the increase of NO3- concentration, the content of P, Fe and K increased under low Ca(NO3)2 concentration, then declined. The content of P and Ca increased with the increasing of NO3- from 14 to 98 mmol·L-1 , and reached the maximum while NO3- was 98 mmol·L-1 under KNO3 , then declined. However,the content of Fe gradually declined. Under NaNO3 treatment, P, K, Ca and Fe content in leaf and root were lower than control.5. Two kinds of sodium salts inhibited the growth of cucumber seedlings. Compared with under NaCl treatment, the biomass, root absorbability and photosynthesis rate were lower under NaNO3, but osmotic potential, osmoregulation substance content, MDA content, the relative electronic leakage and protective enzyme activity were higher than under NaNO3. Which was because the content of Na+ of cucumber seedlings under NaNO3 was remarkably higher than under NaCl, high Na+ concentration has the poison function on cucumber seedlings. The growth of cucumber seedlings under NaCl was better than under NaNO3, but worse than under Ca(NO3)2 and KNO3.更多还原