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甘蔗(Saccharum officinarum L.)是世界上最重要的一类糖料经济作物。全世界75%的糖来源于甘蔗,中国糖业对国内生产总值(GDP)的贡献约为60~80亿元人民币,约占中国国内生产总值(GDP)的0.1%[1]。甘蔗虫害严重危害甘蔗产量,影响甘蔗品质,随着转基因技术的日益成熟,利用转基因的方法将外源抗虫基因导入甘蔗基因组,能够有效的防治甘蔗虫害,提高甘蔗产量。然而,转基因作物带来的生态安全问题不容小觑,这其中就包括转基因作物对土壤生态系统带来的影响,主要表现为对土壤的养分、理化性质、酶活性、土壤中动植物及微生物的影响。近年来,转基因作物对土壤生态系统的影响已成为对转基因作物进行安全性评价的研究热点[2]。土壤微生物参与有机质分解、腐殖质形成、养分转化和循环等一系列生化过程,是土壤生物活性的重要组成部分。土壤酶主要由土壤微生物及植物根系产生,土壤酶活性与土壤其他性质密切相关,如容重、土壤pH值、养分和SOM的分布等[3-4]。土壤酶活性反映了土壤内有机质的动态变化以及土壤内C,N,S,P等元素的物质循环,是评价土壤质量的重要指标。根际是植物、土壤和微生物相互作用的关键区域。外源基因可能通过根系分泌物、植物掉落的残体或花粉进入土壤[5-7]。研究转基因作物根际土壤酶活性,有助于了解外源表达基因产物对土壤微生态的影响。目前,已有许多研究报道了转Bt基因作物对土壤酶活性的影响,但实验结果因不同的转基因作物甚至不同的转基因株系而存在很大的差异。就Bt转基因玉米而言,颜世磊等[8]在大田自然条件下比较研究了转Bt基因玉米种植和秸秆分解时对土壤酶活性影响的差异。结果表明,在喇叭口期和抽雄期,土壤蔗糖酶和土壤酸性磷酸酶活性显著提高。在秸秆还田后,土壤蔗糖酶的活性则有显著提高。作者认为Bt玉米及秸秆还田对土壤酶活性存在影响,影响的幅度及趋势随玉米生育期和土壤酶种类的不同而产生差异,并指出商业化Bt玉米的环境释放仍有待长期定位观测和评价;范巧兰等[9]也认为转Bt基因玉米对土壤酶活性有一定的影响。推测种植Bt玉米对土壤酶活性的影响可能是因根系分泌的Bt蛋白引起土壤微生物多样性的变化而导致,另一种推测是外源 Bt基因导入后引起玉米秸秆以及根系分泌物化学成分的差异而造成;刘玲[10]等认为转Bt玉米对碱性磷酸酶在个别生育期影响显著。然而Flores等[11]、Icoz等[12]则认为转基因玉米对土壤酶活性没有显著影响。而Bt转基因棉花对根际土壤酶活性的影响同样存在不一致的现象。范巧兰等[2]、万小羽等[13]、Sun等[7]认为转基因棉花不同生育期对土壤酶活性有一定的影响;Shen等[14]则认为转基因棉花对土壤脲酶、碱性磷酸酶、蛋白酶等活性没有影响。转Bt基因甘蔗的研究跟其他作物相比相对落后,仅见Zhou等[15] 报道了关于转基因cry1Ac抗虫甘蔗对土壤脲酶、蛋白酶、蔗糖酶活性等的影响,实验结果显示与对照比较,不同的转基因甘蔗株系在个别生长时期的根际土壤酶活性存在显著差异,但总体而言多数土壤样品中没有显着差异。众所周知,甘蔗是多年宿根作物,因此转Bt基因甘蔗一般也会宿根种植3~4年,这种情况下极有可能导致Bt蛋白在土壤中富集,从而影响土壤的生物活性。因此为了更确切地探究种植转Bt基因甘蔗对根际土壤酶活性的影响,本研究以种植转Cry1Ac-2A-gna基因甘蔗优良株系Bt2,Bt17连续宿根3 a的大田土壤作为研究对象,测定不同生长时期转Cry1Ac-2A-gna基因甘蔗对其根际土壤酶活性的影响,为株系Bt2、Bt17的环境释放提供科学的数据支持。
Effect of Insect-resistant Transgenic Sugarcane on Soil Enzyme Activities in the Rhizosphere
doi: 10.15886/j.cnki.rdswxb.2020.01.001
- Received Date: 2019-04-19
- Rev Recd Date: 2020-01-02
- Available Online: 2020-07-03
- Publish Date: 2019-11-01
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Key words:
- insect-resistant transgene /
- sugarcane /
- soil enzyme activity /
- ecological risk
Abstract: In order to assess the ecological risks of insect-resistant transgenic sugarcane lines Bt2 and Bt17 on soil ecological environment rhizosphere soil samples were collected from plantations of insect-resistant transgenic sugarcane lines Bt2 and Bt17 and their non-transgenic donor sugarcane variety ROC22 to analyze the effect of the insect-resistant transgenic sugarcane lines on the activities of soil sucrase, acid phosphatase, neutral phosphatase and alkaline phosphatase in the rhizosphere. The results showed that the effects of the insect-resistant transgenic sugarcane lines on the soil enzyme activities in the rhizosphere varied greatly with the growth cycle of sugarcane, the insect-resistant transgenic sugarcane lines and the enzymes. Soil enzyme activity of sugarcane line Bt2 was not different from that of the control at all the stages of sugarcane growth, while the effect of Bt17 on soil enzyme activity was more complex. Compared with the non-transgenic donor sugarcane ROC22, the sugarcane line Bt17 was not different in soil sucrase activity in the rhizosphere at any stage of sugarcane growth, significantly higher in soil acid phosphatase activity at any stage of sugarcane growth, significantly higher in neutral phosphatase activity at seedling stage, at tillering stage and at mature stage, but not different in neutral phosphatase activity at the grand growth stage, but significantly lower in neutral phosphatase at the tillering stage and the mature stage. This indicated that the sugarcase line Bt2 had no effect on soil enzyme activity in the rhizosphere, while the sugarcane line Bt17 might have less effect on soil enzyme activity in the rhizosphere.
Citation: | FENG Cuilian, WAN Yue, ZHAO Tingting, WANG Jungang, FENG Xiaoyan, ZHANG Shuzhen. Effect of Insect-resistant Transgenic Sugarcane on Soil Enzyme Activities in the Rhizosphere[J]. Journal of Tropical Biology, 2020, 11(1): 1-6. doi: 10.15886/j.cnki.rdswxb.2020.01.001 |