【作者】 杨金凤；

【导师】 温祥珍；

【作者基本信息】 山西农业大学 ， 农业硕士（专业学位）， 2018， 硕士

【摘要】 随着现代农业的不断发展,化肥的施用量不断增加,进而导致Ca(NO3)2的过量积累,对植物的正常生长造成胁迫。大量研究证明,在C02浓度升高时,植物的生物量及其产量均有所增加,且高浓度的CO2可以提高植物的抗逆性。黄瓜(Cucumis sativus L.)作为一种经济蔬菜,其设施栽培面积越来越多。因此,从Ca(NO3)2胁迫的角度可以更加明确的揭示C02加富缓解黄瓜盐胁迫的作用机理。本试验以黄瓜为材料,研究CO2加富缓解硝酸钙胁迫下黄瓜幼苗的生长情况,及其光合特性和体内活性氧代谢及抗氧化酶系统的活性,为进一步了解C02加富缓解黄瓜Ca(NO3)2胁迫的生理机制奠定基础。主要研究结果如下:1.Ca(NO3)2胁迫下,黄瓜幼苗的叶面积以及地上部鲜重显著下降17.75%和41.41%,从显微结构上来看,其海绵组织的厚度明显下降,CO2加富后,黄瓜幼苗的叶面积以及地上部鲜重下降显著减缓,降低了 14.32%、23.83%,其海绵组织的厚度下降明显减缓。说明C02加富在一定程度上能够有效降低Ca(NO3)2胁迫对设施黄瓜幼苗生长的危害。2.Ca(NO3)2胁迫下,黄瓜幼苗的净光合速率显著降低35.84%,气孔导度与蒸腾速率也有所下降。C02加富后,净光合速率显著增加43.07%,气孔导度与蒸腾速率也同样显著上升,单一进行CO2加富后,黄瓜幼苗叶片中的叶绿素a与叶绿素b的含量均显著下降26.69%和26.59%。以上结果表明,C02加富能有效提高黄瓜幼苗的净光合速率与气孔导度,且长时间进行CO2加富处理有可能造成黄瓜幼苗出现了光适应现象。3.Ca(NO3)2胁迫下,叶片与根系中超氧阴离子自由基O2-和MDA的含量则显著上升22.64%和126.38%,并且Ca(NO3)2胁迫会导致根系CAT活性显著增加;C02加富会显著降低各时期Ca(NO3)2胁迫下黄瓜幼苗根部的CAT活性,但即便如此,其CAT活性依旧高于对照组。Ca(NO3)2胁迫下CO2加富显著增加了超氧化物歧化酶(SOD)和过氧化物酶(POD)的活性,降低了黄瓜幼苗超氧阴离子自由基O2-和MDA的含量。表明C02加富可以通过增加SOD和POD的活性来有效清除活性氧,缓解脂膜过氧化带来的伤害,并且进一步减弱Ca(NO3)2胁迫对于黄瓜幼苗带来的生长方面的抑制。4.在CO2加富后,黄瓜幼苗根系中K+的含量显著增加,Na+的含量随着处理时间的延长不断降低;CO2加富与Ca(NO3)2胁迫同时进行下,黄瓜幼苗的叶片与根系中K+的含量减少,Ca2+含量在第六天和第九天显著低于Ca(NO3)2胁迫处理,根系Na+含量均显著低于Ca(NO3)2胁迫处理,并进一步降低了根系对Mg2+的吸收,叶片在第六天对Mg2+的吸收出现峰值,但整体吸收强度降低。这说明,CO2加富可以通过降低K/Na,来减缓Ca(NO3)2胁迫对黄瓜幼苗生长的影响。更多还原

【Abstract】 With the continuous development of modern agriculture,the application amount of chemical fertilizers continues to increase,which in turn leads to excessive accumulation of Ca(NO3)2 and stresses the normal growth of plants.A large number of studies have shown that when the CO2 concentration increases,the plant biomass and its yield increase,and high concentrations of CO2 can improve the plant’s stress resistance.As an economic vegetable,cucumber(Cucumis sativus L.)has more and more facilities for cultivation.Therefore,from the perspective of Ca(NO3)2 stress,the mechanism of CO2 enrichment to alleviate the salt stress of cucumber can be more clearly revealed.In this experiment,cucumber was used as a material to study the growth of cucumber seedlings under CO2 enrichment,and its photosynthetic characteristics,reactive oxygen species metabolism and activity of antioxidant enzyme system in order to further understand CO2 enrichment to alleviate cucumber Ca(NO3)2 laid the foundation for the physiological mechanism of stress.The main findings are as follows:1.Ca(NO3)2 under duress,leaf area of cucumber seedlings and aboveground fresh weight significantly by 17.75%and 41.41%,from the perspective on the microstructure,the thickness of spongy tissue decreased obviously,CO2 enrichment,the leaf area of cucumber seedlings and aboveground fresh weight decreased significantly slowed,was reduced by 14.32%,23.83%,the thickness of spongy tissue slowed down significantly.It is suggested that CO2 plus enrichment can effectively reduce the harm of Ca(NO3)2 stress on the growth of cucumber seedlings.2.Under the stress of Ca(NO3)2,the net photosynthetic rate of cucumber seedlings significantly decreased by 35.84%,and the stomatal conductance and transpiration rate also decreased.After CO2 enrichment,net photosynthetic rate was significantly increased by 43.07%,stomatal conductance and transpiration rate were also significantly increased,single,after CO2 enrichment in cucumber seedling leaf chlorophyll a and chlorophyll b content were significantly decreased by 26.69%and 26.59%.The above results show that CO2 plus enrichment can effectively improve the net photosynthetic rate and stomatal conductance of cucumber seedlings,and the long time of CO2 enrichment treatment may result in light adaptation of cucumber seedlings.3.Under the stress of Ca(NO3)2,the content of superoxide anion free radical O2-and MDA in the leaves and root system increased by 22.64%and 126.38%,and Ca(NO3)2 stress resulted in significant increase of CAT activity in root system.In addition,CO2 could significantly reduce the CAT activity in the root of cucumber seedlings under the stress of Ca(NO3)2 at all times,but even so,the CAT activity was still higher than that of the control group.The activity of superoxide dismutase(SOD)and peroxidase(POD)was significantly increased under Ca(NO3)2 stress,which reduced the content of superoxide anion radical O2-and MDA in cucumber seedlings.It is shown that CO2 and enrichment can effectively remove the active oxygen by increasing the activity of SOD and POD,alleviate the damage caused by lipid peroxidation,furthermore,the inhibition of Ca(NO3)2 stress on the growth of cucumber seedlings was further weakened.4.After CO2 plus enrichment,the content of K+ in the root system of cucumber seedlings increased significantly,and the content of Na+decreased with the extension of processing time.CO2 enrichment and Ca(NO3)2 stress at the same time,the cucumber seedling leaves and roots of reduce the content of K+,Ca2+content in the sixth and the ninth days,significantly lower than that of Ca(NO3)2 stress root Na+ content were significantly lower than that of Ca(NO3)2 stress treatment,and to further reduce the root to the absorption of Mg2+,leaves appear on the sixth day of Mg2+ absorption peak,but the overall absorption intensity is reduced.This indicates that CO2 plus enrichment can reduce the effect of Ca(NO3)2 stress on the growth of cucumber seedlings by reducing K/Na.更多还原