【作者】 张欣；

【导师】 郭笃发； 范仲学；

【作者基本信息】 山东师范大学 ， 环境科学， 2011， 硕士

【摘要】 镉(Cd)是环境中迁移性和毒性最强的重金属元素之一。菠菜对Cd有较强的吸收能力,且是人们喜食的绿叶蔬菜之一。随农田污染日益严重,菠菜生长易受Cd污染危害。因此,研究降低菠菜吸收积累Cd的方法亟待进行。本论文利用盆栽试验,较为系统的研究了Cd影响菠菜生长及其Cd积累的生理机制,并探索了某些外源物质如硅(Si)、微生物对减少菠菜Cd吸收、积累的影响机理。(1)Cd毒害菠菜实验结果:盆栽试验土壤Cd处理浓度分别为0.17、2.13、6.20、8.47和19.60 mg·kg-1,以强力全能和益农398两个菠菜品种为实验材料。随Cd处理浓度的增加,2个菠菜品种各生长和生理指标的变化趋势分别为:地上部和地下部生物量(鲜重和干重)、可溶性糖含量、VC含量、POD及CAT活性呈显著减小趋势;地上部和地下部Cd含量、土壤有效Cd含量、还原糖含量、质膜透性、MDA含量显著增加;地上部和地下部Cd积累量、地上部P及Pro含量、SOD活性先显著增加后显著减小;地上部N、K含量先显著下降后显著上升。另外,2个菠菜品种叶绿体光合色素含量随Cd含量变化不一致,强力全能显著降低,益农398不明显;可溶性蛋白质含量随Cd浓度增加先降低后上升,但较对照均未达到显著性水平。2个菠菜品种地上部Cd积累量显著高于地下部Cd积累量;在不同Cd水平下,强力全能和益农398地上部Cd积累量分别是地下部Cd积累量的5.53-13.13倍和9.15-16.26倍。从安全角度看,强力全能和益农398地上部Cd含量对照组均未超标,加Cd后菠菜地上部Cd含量出现超标;菠菜Cd积累的富集系数及转运系数均小于1,不符合超积累植物标准。(2)Si缓解实验结果:盆栽试验土壤Cd处理浓度分别为0.17、2.13、6.20、8.47和19.60 mg·kg-1,Si浓度为0、100、200 mg·kg-1(分别标记为CK、T1、T2),组成Si、Cd复合处理。以强力全能为实验材料。加Si使菠菜地上部干重、地下部干重、地上部N、K含量及SOD、POD、CAT活性分别增加了14.4%-75.0%、0.0%-60.9%、2.6%、2.9%、2.0%-15.1%、1.2%-34.2%和2.9%-27.8%;使菠菜地上部Cd含量、地下部Cd含量、土壤有效Cd含量、地上部P含量和MDA含量分别下降了0.7%-46.2%、3.9%-47.9%、0.6%-35%和7.2%-32.1%;且使Cd由地下部向上地上部转移减少,地上部Cd含量相对降低,这可以从Cd积累量的降低率看出。通过对Si浓度比较得出,T2较T1处理更能缓解菠菜Cd毒害。(3)微生物缓解实验结果:采用盆栽方法模拟土壤Cd轻度污染(1 mg·kg-1Cd)状况,研究施入3种微生物菌剂(枯草芽孢杆菌、光合细菌和乳酸菌)对菠菜生长及对Cd吸收的影响。以益农398为实验材料。施入微生物菌剂后,菠菜单株鲜重和干重平均增长幅度分别为18.8%和15.7%,微生物对菠菜生长的促进作用大小为:光合细菌>乳酸菌>枯草芽孢杆菌;此外,菠菜植株Cd含量显著减少,平均下降幅度为14.5%,微生物对菠菜Cd吸收的降低作用大小为:枯草芽孢杆菌>光合细菌>乳酸菌。实验还得到,菠菜植株Cd含量与菌数呈显著负相关。更多还原

【Abstract】 Cadmium (Cd) is one of the most mobile and toxic heavy metals in environment. Spinach has high ability to accumulate cadmium and is a very important green leafy vegetables in China. In the production, spinach is easily polluted by Cd, which is one of the most toxic heavy metalsto both plants and animals. Therefore, it’s necessary to reduce Cd uptake and accumulation in spinach. In this study, these experiments will be carried out to study the physiological mechanism in effects of Cd contents in plants of spinach with a plot experiment. Meanwhile, the possibility to reduce Cd uptake and accumulation in spinach by application of Silicon (Si) or microorganisms will be also studied. The major results were summarized as follows:(1) Cd toxicity experiment results: In a plot experiment, five Cd levels, i.e. 0.17, 2.13, 6.20, 8.47 and 19.60 mg·kg-1 were designed based on the Qiangli Quanneng and Yinong398 which are the different tolerance spinach varieties of cadmium. With the levels of cadmium added in soil, the results showed that: the fresh weight and dry weight of shoot and root, soluble sugar content, Vitamin C content, POD and CAT activities in two varieties all showed upward significantly; Cd contents of shoot and root, available-Cd content, reducing sugar content, Relative electrolyte leakage proline content and MDA content all showed downward significantly; Cd accumulation of shoot and root, K content of shoot, proline content and SOD activity showed significant upward first and then downward significantly; N and K contents of shoot showed significant downward first and then upward significantly. Meanwhile, The chloroplast pigment of two spinach varieties had the different change to Cd with decrease significantly of Qiangli Quanneng and no significant of Yinong398; solutable protein content showed downward first and then upward, but no significantly.Cd accumulation of shoot in two spinach varieties was higher than that of root. The Cd accumulation of shoot in Qiangli Quanneng spinach was 5.53-13.13 times than that of root while 9.15-16.26 times in Yinong398. The Cd contents of shoot were less than standard in no Cd added treatment and then the opposite in Cd added treatments. Values of PAF and TF in two spinach varieties under different Cd levels were all less than 1, and so spinach was not hyperaccumulator.(2) Si alleviating Cd toxicity experiment results: In a plot experiment, five Cd levels, i.e. 0.17, 2.13, 6.20, 8.47, 19.60 mg·kg-1, and three Si levels, i.e. 0, 100, 200 mg·kg-1 were designed based on the Qiangli Quanneng. With the levels of Si added in soil, the increasing rates of dry weight of shoot and root, N and K contents of shoot, SOD, POD and CAT activities were 14.4%-75.0%, 0.0%-60.9%, 2.6%, 2.9%, 2.0%-15.1%, 1.2%-34.2% and 2.9%-27.8% respectively; the decreasing rates of Cd contens of shoot and root, available-Cd content, K content of shoot and MDA content were 0.7%-46.2%, 3.9%-47.9%, 0.6%-35% and 7.2%-32.1% respectively. The decreasing rates of Cd accumulation reflected that Cd content of shoot decreased relatively. We also concluded that the T2 treatment was better than the T1 in alleviating Cd toxicity.(3)Microorganisms alleviating Cd toxicity experiment results: Effect of three kinds of microorganisms on growth and cadmium uptake in spinach was investigated with a pot experiment in greenhouse based on the Yinong398. When plants were supplied with microorganisms, fresh and dry weight per plant were average increased 18.8% and 15.7% respectively and Cd conent in spinach was average decreased 14.5%. Besides, we also concluded that Cd content in plant was negative correlated with microbial concentration significantly.更多还原