Effects of insoluble Zn,Cd,and EDTA on the growth,activities of antioxidant enzymes and uptake of Zn and Cd in Vetiveria zizanioides

A root-bag experiment was conducted to study the effects of insoluble Zn, Cd, and ethylenediaminetetraacetic acid （EDTA） on the plant growth, activities of antioxidant enzymes, proline, glutathione （GSH）, water-soluble proteins and malondialdehyde （MDA） of Vetiveria zizanioides. The V. zizanioides uptake capacity of Zn and Cd also determined. The results showed that plant growth of V. zizanioides was inhibited by Zn and Cd. The shoot dry weight （SDW） and root dry weight （RDW） decrease by 14.2%, 14.1%, 17.0% and 17.3%, 32.5%, 35.7%, respectively, compared to the control without EDTA addition. After adding EDTA, shoot and root dry weight decreased over 10% and 15%, respectively. The toxicity from insoluble Zn and Cd in soil on SDW and RDW of V. zizanioides was in order： Zn＋Cd 〉 Cd 〉 Zn. The activities of superoxide dismutase （SOD）, peroxidase （POD） and catalase （CAT）, and contents of MDA and proline increased significantly, while the contents of GSH and water-soluble proteins decreased markedly with increasing Zn and Cd toxicity. With EDTA, shoot and root Zn concentrations increased in the Zn treatment by 7.3% and 37.4%, and Cd concentrations in the combined Zn and Cd treatment increased by 18.6% and 391.9% compared to the treatment without EDTA. However, Zn and Cd concentrations in shoot and roots decreased in the Cd treatment compared to the plants grown in absence of EDTA, with exception of root Cd concentration in the presence of EDTA.

Influence of root suction on tensile strength of Chrysopogon zizanioides roots and its implication on bioslope stabilization

Root tensile strength is an important factor controlling the performance of bio-slope stabilization works. Due to evapotranspiration and climate factors, the root moisture content and its suction can vary seasonally in practice and may not equal soil suction. The influences of suction and root moisture contents were investigated on Chrysopogon zizanioides(vetiver grass) root tensile strength. The root specimens were equilibrated with moist air in different suction conditions(0, 10, 20, and 50 kPa), prior to root tension tests. The root-water characteristic curve or relationship between root moisture and suction, was determined. The increase in suction resulted in decreased tensile strengths of the grass roots, particularly those with diameter of about 0.2 mm, which constituted 50.7% of all roots. For 1 mm roots, the tensile strength appeared to be unaffected by suction increase. The average root tensile strengths were used to estimate the root cohesion in slope stability analysis to find variation of safety factors of a bioengineered slope in different suction conditions. The analysis showed that the critical condition of slope with the lowest factor of safety would happen when the soil suction was zero and the root suction was high. Such condition may occur during a heavy rain period after a prolonged drought.

Valencene-rich fraction from Vetiveria zizanioides exerts immunostimulatory effects in vitro and in mice

Objective:To decipher the responsible compound present in the aqueous root extract of Vetiveria zizanioides which has tremendous immunomodulatory activity.Methods:Different fractions of the water extract were collected and analyzed for immunomodulatory activity by analyzing in vitro phagocytic activity and nitric oxide production.One fraction VF3 was selected and further analyzed for possible compounds by high performance liquid chromatography and gas chromatography coupled with a mass spectrometer.The in vitro immunomodulatory parameters such as phagocytic index,nitrite content,and tumor necrosis factor-α production in murine macrophages were analyzed.In vivo studies,sheep red blood cell induced haemagglutination titer,the number of antibody-producing cells,and sheep red blood cell induced delayed-type hypersensitivity were analyzed.Cytotoxic studies in L929 normal fibroblasts were also performed.Results:One of the fractions,VF3,was selected and confirmed the presence of an active compound valencene.The in vitro immunomodulatory parameters were significantly(P<0.05)increased by valencene treatment.In vivo studies in Swiss albino mice showed that valencene could significantly(P<0.05)increase haemagglutination titer,the number of antibody-producing cells,and delayed-type hypersensitivity.Cytotoxic studies also showed that valencene did not cause any morphological changes and DNA damage in normal fibroblasts.Conclusions:Valencene possesses immunomodulatory activities and can be commercially exploited for its immunostimulatory potentials.

Leaf Growth of Different Populations of Vetiveria zizanioides

Large sample sampling was adopted in this paper for the statistical analysis of leaves of four populations of Vetiveria zizanioides （ introduced, local wild, domesticated wild populations of different years）. The results showed that four populations varied in different degrees in terms of tiller height, leaf biomass, and leaf biomass ratio. Leaf length, leaf width, and ratio of leaf width to length of different populations also varied, but had similar power-function change regularity, and showed converging leaf biomass growth pattern and leaf growth process.

几种植物浮床的水质净化及水华防治效率

分别构建香根草Vetiveria zizanioides、黄菖蒲Iris pseudacorus、西芹Apium graveolens浮床及其不同组合的植物浮床,并在水体中加入6种不同种类的浮游植物及一种水生动物-斑马鱼Danio rerio,研究不同浮床系统对水质的净化效应及其对水生生物的影响。结果显示三种植物在浮床上能健康生长,其生物量、株高和根长均明显增加,且香根草和黄菖蒲的长势优于西芹。植物浮床均能有效防止水体的中化学需氧量(CODMn)的上升,但各生态浮床植物之间无显著性差异;植物浮床能显著去除水体中的氮(N)、磷(P)营养盐,其中,香根草的去除效果最好,而西芹的效果相对较差。总体而言,在系统中添加斑马鱼能在一定程度上提高浮床系统对水体的净化功能。香根草浮床能显著抑制水体中浮游植物的生长,相对而言其他类型的植物浮床对浮游植物的抑制能力较弱或无显著影响,且不同种类浮游藻类对植物浮床的敏感度不同。香根草和黄菖蒲对生态浮床系统中斑马鱼的生物量具有促进作用,香根草的促进作用大于黄菖蒲。综上所述,香根草是一种优良的浮床植物,可广泛用于水体净化及水华防治,而黄菖蒲可用于城市景观水体的净化。

香根草种子外植体组织培养与快速繁殖

为建立香根草(Vetiveria zizanioides)种子的组织培养和快速繁殖体系,以香根草种子为外材料,进行了种子萌发、丛生芽诱导、愈伤组织诱导与分化及生根研究。结果表明,种子在采收初期发芽率达到90%以上,4℃低温贮藏能有限延长种子的寿命;无菌苗丛生芽诱导系数高达7.3;在MS培养基上,0.5 mg/L的2,4-D对种子愈伤组织诱导效果最佳;愈伤组织在MS+6-BA 2.0 mg/L+IAA 1.0 mg/L上分化率达到55.1%,繁殖系数为15.4;在添加0.2 mg/LIAA的MS培养基上,生根培养效果较好。

种植密度对香根草生长动态及生物量的影响

对不同种植密度下香根草(Vetiveria zizanioides)的株高、分蘖数、地上生物量、地下生物量和根冠比进行了研究,以期为香根草规范化栽培提供理论依据。结果表明,在香根草生长前期,种植密度对株高、分蘖数增长的影响不显著;生长后期,种植密度对株高、分蘖数增长的影响显著,且低密度处理的香根草株高、分蘖数增长速度比高密度处理的快。生长前期,高密度处理(T4、T5)的香根草地上生物量大,处理T2(4株/m2)、T3(7株/m2)的地下生物量占优势;生长后期,处理T2、T3的地上生物量占优势,处理T1(1株/m2)的地下生物量占优势,所以低密度种植的香根草根冠比高于高密度种植的。4~7株/m2(T2、T3)为香根草的适宜种植密度。

Accumulation of heavy metals in four grasses grown on lead and zinc mine tailings

A field experiment was conducted to compare the growth and metal accumulation of Vetiveria zizanioides, Paspalum notatum, Cynodon dactylon and Imperata cylindraca var. major on the tailings, amended with 10 cm domestic refuse + complex NPK fertilizer(Treatment A), 10 cm domestic refuse(Treatment B) and complex NPK fertilizer(Treatment C) respectively, and without any amendment used as control(Treatment D). The results indicated that V. zizanioides was a typical heavy metal excluder, because the concentrations in shoots of the plants were the lowest among the four plants tested. The most of metal accumulated in V. zizanioides distributed in its root, and transportation of metal in this plant from root to shoot was restricted. Therefore, V. zizanioides was more suitable for phytostabilization of toxic mined lands than P. notatum and C. dactylon, which accumulated a relatively high level of metals in their shoots and roots. It was also found that I. cylindraca var. major accumulated lower amounts of Pb, Zn and Cu than C. dactylon and P. notatum, and could also be considered for phytostalilisaton of tailings. Although the metal(Pb, Zn and Cu) concentrations in shoots and roots of V. zizanioides were the lowest, the total amounts of heavy metals accumulated in shoots of V. zizanioides were the highest among the four tested plants due to the highest dry weight yield of it. The results indicated that V. zizanioides was the best choice among the four species used for phytoremediation(for both phytostabilization and phytoextraction) of metal contaminated soils.

铬解毒机制诱导香根草的生长和抗氧化反应（英文）

本文研究了铬(Cr)对香根草(Chrysopogon zizanioides)生长以及抗氧化防御酶活性的影响,探讨其对Cr的解毒机制。在50 mg/L Cr处理条件下,植物地上部分和地下部分的生长量分别降低了36.8%和45.0%;Cr在植物地下部分的积累量(9807μg/g干重)大于地上部分的积累量(8730μg/g干重)。随着Cr添加量的增加,光合色素和丙二醛含量增加,在30 mg/L Cr处理条件下含量达到最高,之后,随着Cr处理浓度的增加略有下降;同时,抗氧化防御酶(超氧化物歧化酶、过氧化氢酶和过氧化物酶)的活性显著提高,在较高浓度Cr处理下略有下降。同工酶结果显示在高浓度Cr处理下,超氧化物歧化酶、过氧化氢酶和过氧化物酶的条带强度降低。目前研究结果表明,高浓度Cr导致活性氧过量产生,从而增加了对香根草的氧化损伤,而光合色素、丙二醛、抗氧化酶含量的增加表明香根草对Cr有潜在的耐性机制。结果表明,香根草具有对Cr的解毒机制,并可以积累高浓度的Cr。本文为更深入地研究根草对Cr的解毒机制提供了依据。

香根草在流域治理中的应用

香根草[Vetiveria zizanioides(L.)Nash]是治理水土流失问题常用的植物,其根系发达,有较强耐受性和涵水固土作用,同时对水体污染物有富集作用。通过分析香根草生态学特性及流域治理存在的问题,探讨香根草技术在流域治理中的作用,以期为流域治理提供思路。