外源硅對狼尾草屬牧草鎘脅迫的緩解效應(yīng)及其機(jī)制
發(fā)布時(shí)間：2018-08-18 07:42
【摘要】：鎘(Cd)是土壤主要重金屬污染物之一,具有生物毒性強(qiáng)、遷移性大的特點(diǎn),其在植物體內(nèi)積累到一定量會影響植物的物質(zhì)積累和能量代謝而影響植物正常生長。狼尾草屬(Pennisetum Rich.)牧草是一年生或多年生禾本科植物,具有生物量大、耐性強(qiáng)、營養(yǎng)含量高等優(yōu)良特性,是熱帶、亞熱帶和溫帶地區(qū)的重要牧草,也是優(yōu)質(zhì)的能源草和觀賞草,適宜在我國南方種植。本試驗(yàn)以美洲狼尾草(Pennisetum americanum)和雜交狼尾草(P.americanum×Ppurpureum)為材料,采用土壤盆栽的方法,研究了鎘對狼尾草的毒害機(jī)理,并探討了硅對鎘脅迫下兩種狼尾草的緩解效應(yīng)及其機(jī)制,試驗(yàn)結(jié)果如下:(1)隨著Cd2+濃度增加,兩種狼尾草的株高、鮮重以及干重逐漸降低,但葉寬沒有顯著性變化;兩種狼尾草葉片細(xì)胞膜透性、丙二醛(MDA)含量、可溶性糖含量及脯氨酸含量呈遞增趨勢,在高濃度Cd(Cd40、Cd80)處理下,細(xì)胞膜透性、丙二醛(MDA)含量、可溶性糖含量及脯氨酸含量均顯著增加;低濃度Cd(Cd10、Cd20)處理對兩種狼尾草的超氧化物歧化酶(SOD)、過氧化物酶(POD)和過氧化氫酶(CAT)活性有促進(jìn)作用,高濃度Cd(Cd40、Cd80)處理對兩種狼尾草的超氧化物歧化酶(SOD)、過氧化物酶(POD)和過氧化氫酶(CAT)活性有明顯抑制;Cd處理使兩種狼尾草的凈光合速率(Pn)、蒸騰速率(Tr)及氣孔導(dǎo)度(Gs)顯著下降,而胞間二氧化碳濃度(Ci)升高,且在高濃度Cd(Cd40、Cd80)處理下,兩種狼尾草的葉綠素含量顯著降低。(2)加硅處理明顯緩解了鎘對兩種狼尾草生長的抑制,提高了鎘脅迫下兩種狼尾草的株高、鮮重和干重,其中硅濃度為4.0 mmol·L-1時(shí),對兩種狼尾草株高和鮮干重緩解效果最顯著;不同濃度的硅(1.0、2.0、4.0 mmol·L-1)處理能夠減少兩種狼尾草的丙二醛(MDA)含量,維持脯氨酸含量與可溶性糖含量在一定水平上,提高超氧化物歧化酶(SOD)、過氧化物酶(POD)和過氧化氫酶(CAT)活性,減輕了膜脂過氧化程度,其中硅濃度為2.Ommol·L-1時(shí),能夠顯著提高雜交狼尾草狼尾草在Cd40處理下過氧化物酶(POD)和過氧化氫酶(CAT)活性,硅濃度為4.0 mmol·L-1時(shí),能夠顯著提高兩種狼尾草在Cd80處理下超氧化物歧化酶(SOD)、過氧化物酶(POD)和過氧化氫酶(CAT)活性。其次,硅處理能夠提高鎘毒害下兩種狼尾草葉綠素含量和光合能力,隨著硅濃度增加,兩種狼尾草的凈光合速率、氣孔導(dǎo)度以及蒸騰速率上升,胞間CO2濃度下降,當(dāng)硅濃度為4.0 mmol·L-1時(shí),高濃度Cd(Cd40、Cd80)組的葉綠素含量顯著增加。(3)隨著Cd2+濃度增加,兩種狼尾草的地上部分Cd含量和根系Cd含量逐漸增加,且根系Cd含量大于地上部分Cd含量;加硅處理后,地上部分Cd含量和根系Cd含量下降,隨著硅濃度增加,地上部分Cd含量顯著下降。
[Abstract]:Cadmium (Cd) is one of the major heavy metal pollutants in soil, which has the characteristics of strong biotoxicity and large migration. Its accumulation in plants will affect the accumulation of substances and energy metabolism and affect the normal growth of plants. (Pennisetum Rich.) Forage is an annual or perennial gramineous plant with excellent characteristics of large biomass, strong tolerance and high nutrient content. It is an important forage in tropical, subtropical and temperate regions, and is also an excellent energy and ornamental grass. Suitable for planting in the south of China. In this experiment, (Pennisetum americanum) and P.americanum 脳 Ppurpureum were used as materials to study the mechanism of cadmium toxicity to the two species under cadmium stress, and to explore the mitigation effect and mechanism of the two species under cadmium stress. The results were as follows: (1) with the increase of Cd2 concentration, the plant height, fresh weight and dry weight of the two species decreased gradually, but the leaf width did not change significantly. The content of soluble sugar and proline showed an increasing trend. The cell membrane permeability, malondialdehyde (MDA) content, soluble sugar content and proline content increased significantly under high concentration of CD (CD40) CD80. The activities of (SOD), peroxidase (POD) and catalase (CAT) were promoted by low concentration of CD (CD10 + CD20). The activities of superoxide dismutase (SOD),) peroxidase (POD) and catalase (CAT) were significantly inhibited by high concentration of CD (CD40 + CD80), and the net photosynthetic rate (Pn),) transpiration rate (Pn), transpiration rate (Tr) and stomatal conductance (Gs) of the two species were significantly decreased. However, the concentration of (Ci) increased, and the chlorophyll content of the two species significantly decreased under the high concentration of CD (CD40) CD80. (2) the inhibition of cadmium on the growth of the two species was alleviated, and the plant height of the two species was increased under cadmium stress. Fresh weight and dry weight, of which Si concentration was 4.0 mmol L-1, had the most significant relief effects on the height and fresh dry weight of the two species, and different concentrations of Si (1.0 ~ 2.0 ~ 4.0 mmol ~ (-1) could reduce the malondialdehyde (MDA) content of the two species. The content of proline and soluble sugar were maintained at a certain level, the activities of (SOD), peroxidase (POD) and catalase (CAT) were increased, and the degree of membrane lipid peroxidation was alleviated, especially when the concentration of silicon was 2.Ommol L-1. The activity of peroxidase (POD) and catalase (CAT) were significantly increased by Cd40 treatment, and the activity of peroxidase (POD) and catalase (CAT) were significantly increased when the concentration of silicon was 4.0 mmol L-1. The activity of superoxide dismutase (SOD),) peroxidase (POD) and catalase (CAT) were significantly increased by Cd80 treatment. Secondly, silicon treatment could increase chlorophyll content and photosynthetic ability of the two species under cadmium toxicity. With the increase of silicon concentration, the net photosynthetic rate, stomatal conductance and transpiration rate of the two species increased, while the intercellular CO2 concentration decreased. When the concentration of silicon was 4.0 mmol L-1, the chlorophyll content of the high concentration CD (CD40) CD80 group increased significantly. (3) with the increase of Cd2 concentration, the CD content in the aboveground part and the root system of the two species increased gradually, and the CD content in the roots was higher than that in the aboveground part of CD. After the addition of silicon, the CD content of the aboveground part and the root system decreased, and with the increase of the silicon concentration, the CD content of the aboveground part decreased significantly.
【學(xué)位授予單位】：揚(yáng)州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：X173;S54
，
本文編號：2188796
[Abstract]:Cadmium (Cd) is one of the major heavy metal pollutants in soil, which has the characteristics of strong biotoxicity and large migration. Its accumulation in plants will affect the accumulation of substances and energy metabolism and affect the normal growth of plants. (Pennisetum Rich.) Forage is an annual or perennial gramineous plant with excellent characteristics of large biomass, strong tolerance and high nutrient content. It is an important forage in tropical, subtropical and temperate regions, and is also an excellent energy and ornamental grass. Suitable for planting in the south of China. In this experiment, (Pennisetum americanum) and P.americanum 脳 Ppurpureum were used as materials to study the mechanism of cadmium toxicity to the two species under cadmium stress, and to explore the mitigation effect and mechanism of the two species under cadmium stress. The results were as follows: (1) with the increase of Cd2 concentration, the plant height, fresh weight and dry weight of the two species decreased gradually, but the leaf width did not change significantly. The content of soluble sugar and proline showed an increasing trend. The cell membrane permeability, malondialdehyde (MDA) content, soluble sugar content and proline content increased significantly under high concentration of CD (CD40) CD80. The activities of (SOD), peroxidase (POD) and catalase (CAT) were promoted by low concentration of CD (CD10 + CD20). The activities of superoxide dismutase (SOD),) peroxidase (POD) and catalase (CAT) were significantly inhibited by high concentration of CD (CD40 + CD80), and the net photosynthetic rate (Pn),) transpiration rate (Pn), transpiration rate (Tr) and stomatal conductance (Gs) of the two species were significantly decreased. However, the concentration of (Ci) increased, and the chlorophyll content of the two species significantly decreased under the high concentration of CD (CD40) CD80. (2) the inhibition of cadmium on the growth of the two species was alleviated, and the plant height of the two species was increased under cadmium stress. Fresh weight and dry weight, of which Si concentration was 4.0 mmol L-1, had the most significant relief effects on the height and fresh dry weight of the two species, and different concentrations of Si (1.0 ~ 2.0 ~ 4.0 mmol ~ (-1) could reduce the malondialdehyde (MDA) content of the two species. The content of proline and soluble sugar were maintained at a certain level, the activities of (SOD), peroxidase (POD) and catalase (CAT) were increased, and the degree of membrane lipid peroxidation was alleviated, especially when the concentration of silicon was 2.Ommol L-1. The activity of peroxidase (POD) and catalase (CAT) were significantly increased by Cd40 treatment, and the activity of peroxidase (POD) and catalase (CAT) were significantly increased when the concentration of silicon was 4.0 mmol L-1. The activity of superoxide dismutase (SOD),) peroxidase (POD) and catalase (CAT) were significantly increased by Cd80 treatment. Secondly, silicon treatment could increase chlorophyll content and photosynthetic ability of the two species under cadmium toxicity. With the increase of silicon concentration, the net photosynthetic rate, stomatal conductance and transpiration rate of the two species increased, while the intercellular CO2 concentration decreased. When the concentration of silicon was 4.0 mmol L-1, the chlorophyll content of the high concentration CD (CD40) CD80 group increased significantly. (3) with the increase of Cd2 concentration, the CD content in the aboveground part and the root system of the two species increased gradually, and the CD content in the roots was higher than that in the aboveground part of CD. After the addition of silicon, the CD content of the aboveground part and the root system decreased, and with the increase of the silicon concentration, the CD content of the aboveground part decreased significantly.
【學(xué)位授予單位】：揚(yáng)州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：X173;S54
，
本文編號：2188796
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