發(fā)布時(shí)間：2018-01-09 13:22

  本文關(guān)鍵詞：干旱脅迫對(duì)紫花苜蓿葉片衰老的影響　出處：《仲愷農(nóng)業(yè)工程學(xué)院》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 干旱脅迫 紫花苜蓿 葉片衰老

【摘要】：紫花苜蓿是優(yōu)良的豆科牧草,因其具有養(yǎng)護(hù)容易、抗逆性強(qiáng)、花期長(zhǎng)等優(yōu)點(diǎn),可作為園林景觀地被植物及生態(tài)果園和茶園的護(hù)坡植物在南方地區(qū)開發(fā)和利用,但南方地區(qū)季節(jié)性干旱會(huì)限制紫花苜蓿的推廣與利用。干旱脅迫會(huì)導(dǎo)致紫花苜蓿葉片衰老,影響景觀效果。本研究以兩種抗旱性差異較大的紫花苜蓿為試驗(yàn)材料,采用溫室盆栽方式,對(duì)在干旱脅迫下紫花苜蓿葉綠素含量、葉片衰老率、葉片相對(duì)含水量、光合作用、葉綠素?zé)晒鈪?shù)等葉片衰老特征指標(biāo)進(jìn)行測(cè)定,評(píng)價(jià)了抗旱性強(qiáng)弱不同的紫花苜蓿在干旱脅迫下其葉片衰老特征的差異,同時(shí)研究了6-BA(6-芐氨基嘌呤)對(duì)延緩紫花苜蓿葉片衰老的作用,研究結(jié)果為紫花苜蓿作為景觀植物加以推廣提供了依據(jù)。主要研究結(jié)果如下:(1)干旱脅迫下紫花苜蓿葉片相對(duì)含水量(RWC)下降,水分飽和虧缺(WSD)上升。與抗旱性差的WL-712苜蓿相比,抗旱性強(qiáng)的隴東苜蓿葉片RWC下降幅度及WSD上升幅度均較小,復(fù)水后葉片RWC恢復(fù)程度高。(2)干旱脅迫下兩種紫花苜蓿葉綠素a、葉綠素b及葉綠素(a+b)含量均下降,葉綠素a/b呈上升趨勢(shì)�？购敌詮�(qiáng)的隴東苜蓿葉綠素(a+b)含量降解幅度低,抗衰老能力強(qiáng)。(3)干旱脅迫下紫花苜蓿葉片凈光合速率(Pn)、氣孔導(dǎo)度(Gs)、蒸騰速率(Tr)、胞間二氧化碳濃度(Ci)降低,氣孔限制值(Ls)升高。與WL-712相比,抗旱性強(qiáng)的隴東苜蓿Pn、Tr、Gs、Ci降幅小,Ls升高幅度低,提高了植株的抗旱能力。(4)干旱脅迫下紫花苜蓿葉片PSⅡ潛在活性(Fv/Fo)和PSⅡ反應(yīng)中心光化學(xué)效率(Fv/Fm)降低�？购敌詮�(qiáng)的隴東苜蓿其Fv/Fo、Fv/Fm較抗旱性差的WL-712下降幅度低,復(fù)水后恢復(fù)程度高,具有較強(qiáng)的光合適應(yīng)能力。(5)干旱脅迫造成紫花苜蓿葉片衰老率增加,抗旱性強(qiáng)的隴東苜蓿葉片衰老率低。(6)葉片表面噴施6-BA能顯著提高干旱脅迫下紫花苜蓿葉片RWC,降低葉片WSD,提高葉片的保水能力。(7)葉片噴施6-BA能降低干旱脅迫對(duì)紫花苜蓿葉片細(xì)胞膜的傷害。與未噴施6-BA的干旱處理相比,噴施6-BA能降低紫花苜蓿葉片相對(duì)電導(dǎo)率的上升幅度。(8)葉片噴施6-BA可提高干旱脅迫下紫花苜蓿葉片葉綠素a含量及葉綠素(a+b)含量,復(fù)水后葉綠素a、葉綠素(a+b)含量接近對(duì)照或高于對(duì)照,有效緩解干旱脅迫對(duì)光合色素的降解作用。(9)干旱脅迫下,噴施6-BA的紫花苜蓿葉片衰老率低,對(duì)比抗旱性弱的WL-712,抗旱性強(qiáng)的隴東苜蓿葉片衰老率的降幅較大。
[Abstract]:Alfalfa is an excellent legume forage, because of its easy maintenance, strong resistance, long flowering period and other advantages, it can be used as landscape cover plants, ecological orchards and tea garden slope plants in the southern region development and utilization. But seasonal drought in southern China will limit the spread and utilization of alfalfa. Drought stress will lead to alfalfa leaf senescence. In this study, two alfalfa varieties with different drought resistance were used as experimental materials and greenhouse pot culture was used to study the chlorophyll content and leaf senescence rate of alfalfa under drought stress. Leaf senescence characteristics such as relative water content, photosynthesis and chlorophyll fluorescence parameters were measured to evaluate the difference of leaf senescence characteristics of alfalfa with different drought resistance. At the same time, the effect of 6-BA 6-benzyl aminopurine on delaying the senescence of alfalfa leaves was studied. The results provided a basis for the application of alfalfa as landscape plants. The main results were as follows: 1) the relative water content of alfalfa leaves decreased under drought stress. Compared with the WL-712 alfalfa with poor drought resistance, the leaf RWC and WSD of the drought-resistant alfalfa were smaller than those of the drought-resistant alfalfa. The content of chlorophyll a, chlorophyll b and chlorophyll a b of two kinds of alfalfa decreased under drought stress. Chlorophyll a / b showed an upward trend. The content of chlorophyll a b) in Longdong alfalfa with strong drought resistance was low, and its ability to resist senescence was strong. 3) under drought stress, the net photosynthetic rate (PN) of alfalfa leaves was higher than that of alfalfa. Stomatal conductance, transpiration rate and intercellular carbon dioxide concentration were decreased and stomatal limiting value was increased. Compared with WL-712, the drought-resistant alfalfa in east Gansu Province had higher Tr. The decrease of GsCi was small and the increase of GsCi was low. Under drought stress, the photochemical efficiency of PS 鈪，

本文編號(hào)：1401561