汞脅迫對兩種暖季型草坪草生理生化特征的影響

過昱辰++劉瑩瑩++王賽++王瑞瑩++陸小平++王波

摘 要：當前我國土壤汞污染情況日益嚴重，尋找對汞脅迫具有一定抗性的園林植物已刻不容緩。本研究采用盆栽模擬的試驗方法，研究不同土壤汞濃度水平對兩種暖季型草坪草地毯草和假儉草生理生化特征的影響。結(jié)果表明，隨著汞脅迫強度的增加和時間的延長，兩個草種葉片內(nèi)脯氨酸和丙二醛含量持續(xù)上升，可溶性蛋白含量和超氧化物歧化酶活性均呈現(xiàn)出先升高后下降的趨勢，其中地毯草和假儉草超氧化物歧化酶活性最大值分別達到482.98 U·g-1和557.18 U·g-1，地毯草葉片過氧化物酶活性表現(xiàn)為先持續(xù)升高后趨于穩(wěn)定的趨勢，其最大值為1 254.60 U·g-1·min-1，而假儉草過氧化物酶活性則持續(xù)升高，其最大值達到1 510.16 U·g-1·min-1。本研究結(jié)果可為探索草坪草對汞脅迫的適應機制提供一定的理論依據(jù)。

關(guān)鍵詞：汞脅迫；草坪草；生理生化特征

中圖分類號：S688.4 文獻標識碼：A DOI 編碼：10.3969/j.issn.1006-6500.2016.02.004

Effects of Hg2+ on Physiological and Biochemical Characteristics of Two Warm-season Turf Grasses

GUO Yuchen， LIU Yingying， WANG Sai， WANG Ruiying， LU Xiaoping， WANG Bo

（Department of Horticulcture， Soochow University， Suzhou，Jiangsu 215123， China）

Abstract： Currently， the pollution of mercury in soil in China is getting worse. It's extremely urgent to search for the landscape plants with some resistance to mercury stress. This research took the two warm-season turf grasses Carpet grass and Centipede grass as materials， studied the effects of Hg2+ on physiological and biochemical characteristics of them by using the method of pot simulation. The results showed that with the increase of the concentrations of Hg2+ and the processing time of stress， the content of MDA and Pro were increased. At the same time the content of soluble protein and the activities of SOD showed a trend of first rising and then decreasing. The maximum of SOD activities of Carpet grass and Centipede grass were 482.98 U·g-1 and 557.18 U·g-1 respectively. The POD activities of Carpet grass showed the trend of stable after the first sustained increasing， the maximum of POD activities of it was 1 254.60 U·g-1·min-1. While， the POD activities of Centipede grass showed the trend of sustained rising， the maximum of POD activities of it was 1 510.16 U·g-1·min-1. Through comprehensive evaluation of some physiological and biochemical characteristics of two warm-season turf grasses at seedling stage under mercury stress， the conclusion was drawn that Centipede grass has better resistance to mercury stress than Carpet grass. The results of this research could provide a theoretical basis for exploring the adaptation mechanism of turf grasses under mercury stress.

Key words： mercury stress； turf grasses； physiological and biochemical characteristics

隨著科技的進步和社會生產(chǎn)力的極大提高，人口劇增、資源過度消耗、環(huán)境污染、生態(tài)破壞等問題日益突出，我國土壤資源的數(shù)量逐漸減少，質(zhì)量不斷退化，重金屬污染情況日益嚴重，尤其是土壤汞污染問題愈發(fā)嚴峻，其間發(fā)生了一系列具有重大影響的汞污染事件，這對我國農(nóng)作物食品安全帶來嚴重威脅。

土壤中的汞主要來自于工業(yè)“三廢”的排放，含汞農(nóng)藥的使用和污水灌溉，以及城市垃圾的焚燒。此外，大氣中的汞可以通過干濕沉降進入土壤中，在粘土礦物和有機物的吸附作用下，被土壤迅速吸附或固定，富集于表層土壤，造成土壤汞濃度的進一步升高。土壤汞通過植物的富集和食物鏈進入人體，進而危害人類健康。但也有研究表明，生活在重金屬含量較高環(huán)境中的植物在長期的生物適應進化過程中，逐漸形成了對重金屬的抗逆性，其中一些植物能大量吸收環(huán)境中的重金屬元素并蓄積在體內(nèi)，同時植物仍能正常生長。有關(guān)汞對植物生長發(fā)育的影響，國內(nèi)外都有研究，但大多集中在對糧食作物和經(jīng)濟作物產(chǎn)量和品質(zhì)的影響上，對園林植物生長發(fā)育影響的研究并不多。