中国狗牙根(Cynodon dactylon)优良选系的RAPD分析

对采自中国不同地区的6份狗牙根〔Cynodondactylon(L.)Pers.〕优良选系进行了RAPD分子标记实验。选用15个引物共扩增出438条带,平均每个引物扩增出29条带,其中多态性带415条,多态性位点百分率达到59.02%～75.49%。各选系间遗传相似性系数差异较大(0.408～0.672),说明各选系间在DNA水平上存在着丰富的遗传多样性,与新品种C106(爬地青)相比,各选系还存在一定的改良空间。实验结果也表明,RAPD分子标记可成功地用于中国狗牙根优良选系遗传多样性的研究及品种鉴定。

A Study on the Protective Effect of Cynodon dactylon Leaves Extract in Diabetic Rats

Objective To investigate the antidiabetic, antioxidant and hypolipidemic efficacy of Cynodon dactylon in diabetic rats. Methods The experimental rats were randomly divided into three groups： Group I： control; Group II： Alloxan diabetic, untreated; and Group III： Alloxan diabetic treated with ethanolic extract of C. dactylon leaves （450 mg/kg bw）. Experimental diabetes was induced by alloxan in a single dose of 150 mg/kg bw. Results A Significant diminution of fasting blood sugar level was observed and also significant increase in HDL and decrease （P0.05） in cholesterol, triglyceride, LDL and VLDL were observed after 15 days of treatment. The investigation also revealed, the activities of AST, ALT, ALP, AP, LDH, and CPK （P0.05） were decreased in the extract‐supplemented group. The significant decrease in protein content and SOD, CAT, GPx, and GSH （P0.05） activity and increase in LPO in plasma were found to be ameliorated after treatment. Conclusion Our result supports the fact that administration of extract of C. dactylon leave is able to reduce hyperglycemia and hyperlipidemia risk and also reduced the oxidative stress in diabetic rats.

Micromorphology of Leaf Epidermal Cells of Different Species of Cynodon dactylon in Pastoral Soil

To identify suitable grass species for growth in the Jianghan Plain,the micromorphologies of the upper and lower epidermis of the leaves of 14 bermudagrass varieties of Cynodon dactylon were investigated,and the number,length,and width of long and short cells and stomata were measured.The results showed that the anticlinal wall of epidermal cells looked like waves and the stoma was distributed in the upper and lower epidermis.However,the various indicators of the leaf epidermis of different species of Cd were significantly different.The length and width of long cells and the length of short cells of Cd Mohawk,Cd Suncity,and wild type Cd were relatively large,which may improve their ability to adapt to the pastoral soil and make them suitable for the rainy environment of the Jianghan Plain.On the contrary,the results of all indicators of Cd Xinnong 1,Cd hulled,and Cd unhulled ranked at the bottom,which was not suitable for pastoral soil habitats,while the wild type Cd could adapt to both the pastoral soil and the vegetation concrete habitat.Moreover,the long cells and short cells of Cd Kashi were tightly arranged,and the stoma in Cd Pyramid and Cd hulled were more dense,which may improve their ability to adapt to an arid environment.

氮沉降对城市绿地植物及土壤养分的影响初探——以果岭草(Cynodon dactylon)为例

大气氮沉降是近年来全球变化研究的焦点问题之一,大量而持续的氮沉降对陆地生态系统造成了广泛的影响,但关于氮沉降对城市绿地生态系统的影响及其机制仍然缺少足够的研究。通过模拟氮沉降控制试验,以NH_4NO_3作为外加氮源,设置了N0、N1、N2和N3(分别相当于氮沉降0、5、10、15 g·m^(-2)·a^(-1))4个不同处理,历时12个月,探讨不同程度氮沉降增加对典型城市绿化物种果岭草(Cynodon dactylon)生长状况及土壤化学性质的影响。研究结果表明:(1)氮沉降量为5 g·m^(-2)·a^(-1)时,果岭草地上、地下生物量以及植株密度最大;氮沉降量为10 g·m^(-2)·a^(-1)时,株高最高;根冠比随着施氮量的增加呈减小趋势;适量氮沉降处理有利于植株的生长以及生物量的积累;同时,降水的季节变化可能影响植物对氮的吸收利用;(2)城市绿地土壤pH值随施氮量的增加呈减少趋势,低度适量的氮沉降作用于城市碱性土壤可以中和土壤酸碱度,调节土壤pH值;(3)施氮处理使得城市绿地土壤中的有效氮含量和城市绿地生产力得到一定程度提高。本研究结果证明氮沉降将对城市绿地植物及土壤理化性质产生持续的影响,同时一定程度的氮沉降对城市绿地植物生产力的提高具有促进作用。

Anti-chikungunya activity of luteolin and apigenin rich fraction from Cynodon dactylon

Objective:To obtain Iuteolin and apigenin rich fraction from the ethanolic extract of Cynodon dactylon(L.)(C.dactylon) Pers and evaluate the fraction's cytotoxicity and anti-Chikungunya potential using Vero cells.Methods:The ethanolic extract of C.dactylon was subjected to silica gel column chromatography to obtain anti-chikungunya virus(CHIKV) fraction.Reverse phase-HPLC and GC-MS studies were carried out to identily the major phytochemicals in the fraction using phylochemical standards.Cytotoxicity and the potential of the fraction against CHIKV were evaluated in vitro using Vero cells.Reduction in viral replication was assessed by reverse transcriptase-polymerase chain reaction(RT-PCR) after treating the viral infected Vero cells with the fraction.Results:Reverse Phase-HPLC and GC-MS studies confirmed the presence of flavonoids,luteolin and apigenin as major phytochemicals in the anti-CHIKV ethanolic fraction of C.dactylon- The fraction was found to exhibit potent viral inhibitory activity(about 98%) at the concentration of 50 μg/mL as observed by reduction in cytopathic effect,and the cytotoxic concentration of the fraction was found to be 250 μg/mL.RT-PCR analyses indicated that the reduction in viral mRNA synthesis in fraction treated infected cells was much higher than the viral infected control cells.Conclusions:Luteolin and apigenin rich ethanolic fraction from C.dactylon can be utilized as a potential therapeutic agent against CHIKV infection as the fraction does not show cytotoxicity while inhibiting the virus.

Antidiabetic and antidiarrhoeal potentials of ethanolic extracts of aerial parts of Cynodon dactylon Pers

Objective: To explore the antidiabetic and the antidiarrhoeal effects of ethanolic extracts of Cynodon dactylon Pers. aerial parts(EECA) in Wistar rats.Methods: To assess the antidiabetic activity of EECA, oral glucose tolerance test(OGTT) model and alloxan induced diabetic test(AIDT) model were performed. The EECA was used at the doses of 2 g/kg, 1 g/kg and 500 mg/kg body weight in OGTT model and 1.5 g/kg was used for AIDT model. Castor oil-induced diarrhoeal model and gastrointestinal motility test with barium sulphate milk model were performed for evaluating the antidiarrhoeal effects at doses of 1 g/kg, 750 mg/kg respectively.Results: The dose 2 g/kg in OGTT and 1.5 g/kg in AIDT model blood glucose levels decreased significantly(P < 0.01) in Wistar rats that showed antidiabetic effect of EECA. After administration of EECA at the dose of 1 g/kg, the extract showed significant(P < 0.05) antidiarrhoeal activity in castor oil-induced diarrhoeal model. The results were also significant(P < 0.01) in barium sulphate milk model for the same dose by using above mentioned animals.Conclusions: It is concluded that EECA contains both antidiabetic and the antidiarrhoeal properties.

Cynodon dactylon extract ameliorates cognitive functions and cerebellar oxidative stress in whole body irradiated mice

Objective: To explore the effect of hydroalcoholic extract of Cynodon dactylon on the whole body radiation-induced oxidative status of the cerebellum and cognitive impairments in mice. Methods: Swiss albino mice were randomly divided into the control group, radiation control group, low dose and high dose Cynodon dactylon extract treated groups and pre-treated with Cynodon dactylon extract before irradiation. Cynodon dactylon extract was administered for 7 d daily in low dose(0.25 g/kg) and high dose(1 g/kg). On day 7, mice were irradiated with a sublethal dose of 5 Gy gamma rays. Motor coordination was assessed by elevated rotarod test and spatial memory was studied by water maze test. Subsequently, biochemical markers(glutathione, lipid peroxidation and nitric oxide levels) in the cerebellum were evaluated. Results: The gamma irradiated group showed significant impairment in motor coordination and spatial memory compared to normal mice. Mice treated by Cynodon dactylon extract prior to gamma radiation showed good improvement in both paradigms compared to the radiation control group. Moreover, glutathione level was increased, while lipid peroxidation and nitric oxide levels were significantly reduced in mice receiving low dose and high dose of Cynodon dactylon extract compared to the radiation control group. Conclusions: The present study suggests the neuroprotective role of Cynodon dactylon against radiation-induced cognitive impairment and oxidative stress on the cerebellum of mice.

中国狗牙根〔Cynodondactylon(L.)Pers.〕耐寒性及其变化规律

将49份具有代表性的我国狗牙根〔Cynodondactylon(L.)Pers.〕种源的离体叶片进行模拟低温处理,用电导法测其电导率,将电导率拟合Logistic方程,计算出狗牙根各种源叶片的半致死温度(LT50)。回归分析的结果表明:各种源的LT50与其所在的经纬度呈显著的线性关系,线性回归方程分别为Y=-31.3797+0.1478X和Y=-10.7982-0.1420X。依据LT50的变化,可将这49份狗牙根种源分为3大类,即低温敏感型(LT50≥-10℃)、过渡型(-18℃<LT50<-10℃)和耐寒型(LT50≤-18℃),3类狗牙根的分布具有一定的规律性。对狗牙根的耐寒机理也进行了探讨。

Enhanced Cadmium Accumulation in Transgenic Tobacco Expressing the Phytochelatin Synthase Gene of Cynodon dactylon L

Bermudagrass （Cynodon dactylon L. cv. Goldensun） is highly resistant to and accumulates large amounts of cadmium （Cd）. A phytochelatin synthase （PCS） cDNA （CdPCS1） was isolated from this grass by rapid amplification of cDNA ends. The putative CdPCS1 protein shared a high homology with PCS from other plants, with 79% homology at the N-terminal and 47% homology at the C-terminah However, 16 Cys residues were found at the C-terminal of CdPCS1, and among these residues, three positions were different from other PCS proteins. Semiquantitative reverse transcription-polymerase chain reaction analysis showed that Cd stress induced CdPCS1 expression in both roots and leaves in Bermudagrass. We verified that CdPCS1 plays an important role in Cd tolerance in yeast cells by expressing the gene in ABDE1, a Cdsensitive mutant. CdPCS1 was then introduced into tobacco plants. The phytochelatin level in some transgenic tobacco lines increased 3.88-fold more than in wild type plants and Cd accumulation in these transgenic plants was enhanced 3.21-fold accordingly. The results suggested that CdPCS1 could be used as a gene element for phytoremediation in the future.

Phytochemical analysis and antifertility potential of Cynodon dactylon in female Wistar rats:A herbal approach towards contraception

Objective:The objective of the present study was to evaluate the antifertility activity of ether(ErCD),chloroform(CeCD)and ethyl alcohol(EyCD)extracts of the whole plant of Cynodon dactylon in female Wistar albino rats.Methods:Acute oral toxicity and an antifertility study were performed in female Wistar rats with two dose levels(200 and 400 mg/kg,orally)of EyCD.The estrogenic and progestogenic effects of EyCD were further observed by administering it to immature Wistar rats by investigations of vaginal cornification,hormonal level,uterus weight,biochemical parameters,histopathology of the uterus and deciduoma formation,respectively.Isolation of EyCD was carried out by Flash Chromatography and isolated fraction was estimated by HPLC.Results:No toxicity with any of the extract was found up to the dose of 2000 mg/kg body weight.EyCD treated rats exhibited maximum reduction in pregnancy(83.33%).Estimation of EyCD on vaginal cornification,estrogen-induced uterotrophic assay and deciduoma model demonstrated vaginal cornification,significant(P<0.01)increase in uterine weight and uterine proliferation in histopathology and reduced deciduoma formation respectively.Hormonal and biochemical parameters confirmed the above findings indicating estrogenic potential and antiprogestogenic potential of EyCD that might be attributed to the presence of phytoestrogen(apigenin)in EyCD.Conclusion:The results suggested that extracts of C.dactylon possess significant antifertility activity,which is consistent with the literature reported in folk medicine of this plant in fertility regulation.

NaCl胁迫下pH值和氮素形态对狗牙根生长及钠钾离子调控的影响

以狗牙根〔Cynodon dactylon(Linn.)Pers.〕品种‘阳江’(‘Yangjiang’)为实验材料、2-(N-吗啡啉)乙磺酸(MES)为pH缓冲剂,采用水培法研究NaCl胁迫下pH值和氮素形态(铵态氮和硝态氮)对狗牙根生长和钠钾离子调控的影响。结果表明:处理1周后,若不添加MES,铵态氮处理组培养液的pH值下降到pH 4.0左右,而硝态氮处理组培养液的pH值则上升到pH 9.0左右;添加20 mmol·L^(-1)MES的铵态氮处理组培养液的pH值也下降到pH 4.0左右,而硝态氮处理组培养液的pH值则接近pH 7.0。与0 mmol·L^(-1)NaCl处理组相比,300 mmol·L^(-1)NaCl处理组狗牙根的枝条长度和枝条干质量显著(P<0.05)下降,而根长度、根干质量、根和叶中Na^(+)含量和Na^(+)/K^(+)比、钠钾选择性转运系数、叶Na^(+)和K^(+)的分泌量及分泌物Na^(+)/K^(+)比总体上显著升高。300 mmol·L^(-1)NaCl胁迫下,硝态氮处理组狗牙根的枝条长度、根长度、根干质量、根冠比、根中Na^(+)含量总体上显著高于铵态氮处理组,而叶中Na^(+)和K^(+)含量及Na^(+)/K^(+)比、叶Na^(+)和K^(+)的分泌量明显低于铵态氮处理组。300 mmol·L^(-1)NaCl胁迫下,20 mmol·L^(-1)MES处理组狗牙根的多数生长指标显著高于0 mmol·L^(-1)MES处理组,而根和叶中Na^(+)和K^(+)含量及Na^(+)/K^(+)比、钠钾选择性转运系数在0和20 mmol·L^(-1)MES处理组间的差异不显著。三因素方差分析结果表明:3个因子的单一和交互作用对多数生长指标、叶中Na^(+)含量和泌盐量相关指标的影响具有统计学意义。研究结果显示:硝态氮能缓解NaCl胁迫对狗牙根的伤害,而用MES缓冲根际酸碱环境对NaCl胁迫下狗牙根生长有一定的促进作用,因此,施用硝态氮或添加MES均有利于提高狗牙根的抗盐性。

狗牙根覆盖对三峡库区消落带波浪作用力和侵蚀的影响

波浪侵蚀是三峡库区消落带土壤侵蚀的主要类型,已严重威胁到库区经济发展和生态环境构建。植被修复可以实现水土保持和增强消落带稳定性目的,但关于在波浪作用于消落带上坡面时植物覆盖对波压力和孔隙水压力和侵蚀量的影响及关系尚不明确。为此,设置3个波高(4、6和8 cm)、3个坡面条件(裸坡对照、30%狗牙根覆盖和60%狗牙根覆盖),开展模拟波浪试验,分析不同植被盖度对消落带波浪作用力和侵蚀的影响。结果表明:裸坡时,随波高增加,波压力和孔隙水压力分别增加3.80%~48.62%和13.12%~50.44%,侵蚀量增加0.88%~8.08%。存在植被时,对比裸坡,随波高增加,波压力和孔隙水压力分别降低2.98%~220.17%和15.47%~75.64%,侵蚀量则降低29.31%~80.83%。植物可以通过地上部分和地下部分消散波压力和孔隙水压力,从而提高消落带受波浪作用的耐受性,进而有效降低波浪造成的侵蚀量。以上结果加深了在波浪作用于紫色土消落带坡面时狗牙根覆盖与波浪作用力与侵蚀量关系的理解,为库区消落带植被恢复和水土保持提供一定的参考。

铅胁迫下吲哚乙酸对狗牙根铅累积及生理特性的影响

为明确外源生长素对狗牙根在铅(Pb)胁迫下的作用与机制,本研究以Pb耐性植物狗牙根为对象,在盆栽试验条件下,对处于324.4 mg·kg^(-1)土壤Pb胁迫下的狗牙根叶面喷施不同浓度的(0、1、10、100 mg·L^(-1))吲哚乙酸(IAA)与5、10 mg·L^(-1)的生长素极性运输抑制剂(NPA),探究外源IAA对狗牙根的生长、生理特性及Pb积累的影响。结果表明:外源IAA使狗牙根IAA与细胞分裂素(CTK)含量升高,脱落酸(ABA)含量及吲哚乙酸氧化酶(IAAO)活性降低,促进了狗牙根在Pb胁迫下株高、根长、地上和地下部干重的增加。其中,喷施10 mg·L^(-1)IAA效果最好。与对照相比,10 mg·L^(-1)IAA叶面喷施处理使株高、根长及地上与地下部干重分别提高了32.4%、30.1%、32.2%和25.5%,叶绿素a、叶绿素b、胡萝卜素含量分别升高到对照组的1.35、1.36和1.21倍,叶与根中的Ca2+与可溶性蛋白含量显著上升。10 mg·L^(-1)IAA叶面喷施还改善了狗牙根体内的抗氧化指标,表现为丙二醛(MDA)含量相较于对照组显著下降,过氧化物酶(POD)活性显著升高。此外,10 mg·L^(-1)IAA叶面喷施促进了根对Pb的吸收和固定,同时抑制Pb的根-冠转移。但喷施NPA加重了Pb对狗牙根的生长抑制且该生长抑制具有对NPA的剂量依赖效应,10 mg·L^(-1)NPA的抑制效果最强,削弱了狗牙根内源激素对Pb的应激效应、降低了叶绿素荧光参数与光合色素含量、提高了狗牙根地上部分Pb含量、导致MDA含量升高。综合分析表明,本试验条件下狗牙根喷施10 mg·L^(-1)IAA效果最佳,通过增强狗牙根对Pb的激素应激反应、提高光合作用和抗氧化能力改善了植株生长;同时通过提升胞内Ca2+与可溶性蛋白含量抑制了Pb的根冠迁移,从而降低膜脂质过氧化水平,缓解了Pb胁迫下狗牙根的氧化损伤。本研究结果丰富了狗牙根耐Pb机制,并为应用外源IAA缓解植物Pb毒害提供了科学依据。

药用植物狗牙根的化学成分及其抗炎活性研究

综合采用正相、反相硅胶柱色谱、Sephadex LH-20凝胶柱色谱、半制备液相色谱等色谱方法进行化学成分分离纯化,运用核磁共振和质谱等波谱方法鉴定化合物的结构,对药用植物狗牙根[Cynodon dactylon(L.)Pers.]95%乙醇提取物进行化学成分研究,并对其中的黄酮类和蒽醌类进行抗炎活性研究.从狗牙根全草中分离得到16个化合物,分别鉴定为苜蓿素(1)、chrysoeriol(2)、isoliquiritigenin(3)、tricin 4′-O-(threo-β-guaiacyl-(7′′-O-methyl-9′′-O-acetyl)-glyceryl)ether(4)、木犀草素(5)、tricin 4′-O-(erythro-β-guaiacylglyceryl)ether(6)、calquiquelignan D(7)、calquiquelignan E(8)、5,5′-dihydroxy-2′,4′-dim-ethoxyflavone-7-O-β-D-(6′′-O-Zp-coumaroyl)-glucopyranoside(9)、4′-hydroxy-2,3-dihydroflavone-7-β-D-glucopyranoside(10)、tricin 4′-O-(threo-β-guaiacyl-(7′′-O-methyl)-glyceryl)ether(11)、ω-Hydroxyemodin(12)、phomarin(13)、aurantio-obtusin(14)、β-谷甾醇(15)、豆甾醇(16).除化合物5外,其他化合物均为首次从该植物中分离得到,其中化合物2、3和14显示显著抗炎活性,其IC50值分别为2.74、2.35、3.61μmol/L.

6种常见草坪草抗退化能力评估研究

为探讨利用常规植物生长数据评估草坪草抗退化能力的可行性,选取6种常见草坪草为研究对象,设置保持自然状态和人工去杂2个试验处理,连续5年调查单位面积植物物种多样性、植株个体数量和植物年生长量,分析3组数据随建坪年限增长的变化趋势和规律。结果表明,人工去杂管理措施能够显著减少各类草坪的杂草数量,保证草坪的整齐度和观赏性。随着建坪年限的增长,6种草坪单位面积植物物种多样性均呈衰减指数模型分布;人工去杂试验处理中白花三叶草的衰变速率最快,说明人工去杂管理措施对白花三叶草草坪管理效果最明显;保持自然状态样地中狗牙根和高羊茅的衰变速率最快,且在样方中仍然为优势植物种,说明两者的竞争能力较强。由于繁殖方式不同,单位面积植株个体数量在狗牙根草坪2个试验处理中呈二项式模型分布,在其他5种草坪中呈衰减指数模型分布。植物年生长量在6种草坪中均呈二项式模型分布,其达到最大值所需时间在人工去杂样地中匍匐剪股颖最长,在保持自然状态样地中狗牙根时间最长,说明人工去杂管理措施延缓匍匐剪股颖草坪退化的效果最明显,保持自然状态下狗牙根的竞争能力最强。研究结果表明,用单位面积植物物种多样性、植株个体数量和植物年生长量3组数据均能评价和衡量草坪草的抗退化能力,可以作为不同地区根据当地气候条件和草坪建成后的使用目的选择相应草坪草品种提供科学建议和合理意见,以便提高草坪质量,延缓草坪退化现象,延长草坪使用寿命。

长期完全水淹对4种三峡库区岸生植物存活及恢复生长的影响

地瓜藤(Ficus tikoua)、荻(Triarrhena sacchariflora)、牛鞭草(Hemarthria altissima)和狗牙根(Cynodon dactylon)是三峡库区常见的岸生植物,自然分布于河岸带不同垂直高程的地段。为了明确它们在成库后"三峡库区消落区"长期完全水淹条件下的存活和生长情况,实验设置对照(不进行水淹,常规供水管理)和完全水淹两个处理,30、60、90、120、150和180d6个水淹时间水平,研究了4种植物在完全水淹条件下的存活、生物量变化和恢复生长。结果发现:1)4种植物在完全水淹条件下的存活率与其在河岸带上的垂直分布高程密切相关。分布于距江面高程较高的河岸段的地瓜藤植株,在全淹30d后就全部死亡;分布在中高程河岸段的荻在全淹150和180d后全部死亡;可以分布于低高程河岸段的牛鞭草和狗牙根,淹没180d后存活率分别为90%和100%。2)全淹抑制了荻、牛鞭草和狗牙根的生长,总生物量增量显著低于对照植株。与水淹0d相比,全淹处理植株的地上部分生物量显著降低,荻在全淹60和120d后,地下部分生物量显著降低,但牛鞭草和狗牙根的地下部分生物量与水淹0d水平相比无显著差异。3)水淹处理结束后,存活的荻、牛鞭草和狗牙根植株都能很好地恢复生长。在恢复生长过程中,全淹30、60和90d后,荻、牛鞭草和狗牙根植株的总分枝长相对生长速率与对照植株无显著差异,全淹120、150和180d后,牛鞭草和狗牙根植株的总分枝长相对生长速率显著高于对照植株。全淹处理的荻、牛鞭草和狗牙根植株的总叶片数相对生长速率始终显著高于对照植株。遭受长期完全水淹后,植株在有限的营养储备条件下,快速产生叶片以迅速积聚光合产物可能是植物更为优化的恢复生长方式。

野生狗牙根种质遗传多样性的SRAP研究

采用SRAP分子标记技术,对采自中国四川、重庆、贵州、西藏四省区的32份野生狗牙根(Cynodon dactylon)材料进行遗传多样性分析,获得下述结果:(1)用14对引物组合共得到132条多态性条带,平均每对引物扩增出9.4条多态带,多态性位点百分率为79.8%,材料间的遗传相似系数范围在0.591到0.957之间,平均GS值为0.759,这些结果说明,供试野生狗牙根具有较为丰富的遗传多样性;(2)对所有材料进行聚类分析,可聚为4类,大部分来自相同或相似生态地理环境的材料聚为一类,表明供试材料的聚类和其生态地理环境间有一定的相关性;(3)基于Shannon多样性指数估算了6个狗牙根生态地理类群内和类群间的遗传分化,发现类群内遗传变异占总变异的65.56%,而类群间遗传变异占总变异的34.44%;(4)对各生态地理类群基于Nei氏无偏估计的遗传一致度的聚类分析表明,各生态地理类群间的遗传分化与其所处的生态地理环境具有一定的相关性。

三峡库区狗牙根对深淹胁迫的生理响应

选取三峡库区自然消落带野生狗牙根(XC)和非消落带野生狗牙根(FC)为研究对象,采用三重复裂区设计试验,主区为两品种,副区为6个不同深度水淹处理(0,1,2,5,10m和15m),分析了各处理植株几种酶活性和碳水化合物含量的变化情况。结果显示:①不同生境狗牙根受深淹胁迫后,丙二醛(MDA)都呈递增趋势,表明狗牙根在深淹胁迫下受到了不同程度的膜脂过氧化伤害,且随胁迫程度的增加受伤害增大。②超氧化物歧化酶(SOD)、过氧化物酶(POD)、谷胱甘肽还原酶(GR)活性和醇脱氢酶(ADH)活性较对照都有所增加;XC处理POD和SOD的最大值出现在5m深水淹处理,而FC出现在2m深处理,且XC5米深淹处理GR值较对照和其他处理明显大;各受淹处理地下茎可溶性糖含量和淀粉含量都保持在较高水平。③从抗氧化酶活性和ADH活性的变化规律,以及淹水胁迫下植株的能量代谢情况,初步得出XC与FC都具有一定的耐淹性,且XC较FC具更耐深淹的能力,表明狗牙根作为禾本科植物遗传上具有一定的耐淹性,自然消落带狗牙根因长期生长于水淹胁迫环境,耐淹能力得到了进一步强化。从狗牙根对深淹胁迫的生理响应上,证明狗牙根是宜用于三峡水库消落带植被恢复的物种。

长期深淹对三峡库区三种草本植物的恢复生长及光合特性的影响

硬秆子草(Capillipedium assimile)、双穗雀稗(Paspalum distichum)和狗牙根(Cynodon dactylon)在经受与三峡水库水位运行节律基本一致的水淹时间和水淹持续时期,但淹水深度(0、5、15和25m)不同的处理后,对其进行了恢复生长和光合特性研究。结果表明:(1)3种草本植物之间相比,狗牙根的存活率最高,所有处理植株存活率达到了100%;硬秆子草和双穗雀稗随着水淹深度的增加,存活率呈降低趋势,5m深处理存活率达到了100%,15m和25m深处理存活率在80%以上。(2)3种草本植物恢复生长后的叶片净光合速率Pn、蒸腾速率Tr、气孔导度Gs、水分利用效率WUE和表观CO2利用效率CUEapp与未淹对照相比没有显著差异;不同物种相同水淹处理之间比较,狗牙根的各光合指标显著高于硬秆子草和双穗雀稗。(3)结合三峡库区消落带植被恢复物种筛选的基本条件和本试验不同处理植株的恢复生长及其光合特性的研究,结果表明,硬秆子草、双穗雀稗和狗牙根是能够忍耐长期深淹胁迫的、适宜于三峡库区消落带植被恢复与重建的优良物种。三者之间的耐淹能力从大到小依次为:狗牙根>硬秆子草>双穗雀稗。

西南五省区及非洲野生狗牙根种质基于SRAP标记的遗传多样性分析

利用SRAP分子标记技术,对采自中国西南5省区的44份野生狗牙根及8份非洲狗牙根材料进行遗传多样性研究。结果表明,18对引物组合共得到扩增总条带236条,多态性条带数206条,平均每对引物扩增出11.4条带,多态性位点百分率为87.29%,材料间的遗传相似系数范围为0.569-0.929,平均GS值为0.723。聚类分析结果表明,52份材料可聚为5类;基于Shannon多样性指数估算了8个狗牙根生态地理类群内和类群间的遗传分化,类群内的遗传变异占总变异的63.81%,类群间的遗传变异占总变异的36.19%,表明这些抗源材料遗传差异较大,各生态地理类群间的遗传分化与其所处的生态地理环境具有一定的相关性。