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51.
为获得甘肃中部地区旱作种植条件下合理的苜蓿收割制度参数,在陇西县文峰镇典型黄土高原丘陵山地,以秋眠级5级的三得利苜蓿为例,研究不同刈割次数与苜蓿产草量、鲜干比、茎叶比、越冬性能以及营养物质含量等几个主要经济性状的关系.结果表明:在保证苜蓿正常越冬的条件下,每年刈割4次和3次处理组比每年刈割2次的处理组产草量提高7.13...  相似文献   
52.
富硒区茶树鲜叶中硒累积与土壤因子的相关性分析   总被引:1,自引:0,他引:1  
茶树是富硒植物,饮用富硒茶是一种安全、有效的补硒途径之一。茶叶的硒含量受多种环境因素影响,但有关富硒茶区茶树硒积累特性及主要影响因子的研究还鲜有报道。以高硒茶区湖北恩施、陕西安康不同地点生产茶园成龄茶树和根际土壤为研究对象,结合土壤及植物样品全硒含量等多种指标,明确了根际土壤硒含量对茶树硒分布特性的影响,分析了富硒区土壤pH、硒含量等9个重要土壤特性相关因子的数值分布规律。通过对186组具有代表性的土壤样品和附生茶树新梢组织检测数据进行分组和整体相关性分析,证实了富硒区茶叶全硒含量与土壤硒含量之间存在极显著相关(相关系数r=0.59,P<0.01),揭示了茶叶全硒含量与土壤有机质含量、水解性氮、锌含量以及茶叶中硫、锌含量的显著相关,同时对安康和恩施地区的土壤和茶叶硒含量相关因素进行了深入分析。提出了茶叶硒含量对土壤有机质含量、硫含量、硒含量和锌含量的数学模型,模型拟合优度为0.512 6,达极显著水平(P<0.01)。  相似文献   
53.
Efforts to control viral diseases of grapevine include the production of certified material and development of virus-resistant transgenic grapevines. However, effective antiviral agents, once the viruses have infected the plants, are still lacking. This study shows that a crude garlic extract has significant antiviral activity against grapevine viruses. Replication of grapevine leafroll-associated virus 2 (GLRaV-2) was obviously inhibited in grapevine cv. Cabernet Sauvignon calli treated with diluted (1:100) garlic extract. The relative RNA levels of GLRaV-2 and grapevine fleck virus (GFkV) in cv. Summer Black grapevine in in vitro-grown plantlets 10 days after treatment with diluted (1:100) garlic extract were about 22% and 20%, respectively, of that in controls. The viral RNA accumulation of GLRaV-2, GFkV, grapevine virus A (GVA), grapevine fanleaf virus (GFLV) and grapevine rupestris stem pitting-associated virus (GRSPaV) in field-grown grapevine cv. Centennial Seedless plants sprayed with diluted (1:100) garlic extract were about 31–40%, 26–38%, 18–31%, 17–42% and 15–18%, respectively, of that in controls. Moreover, the garlic extract treatment led to a significant decrease in viral RNA accumulation of GLRaV-3, GLRaV-2, GVA, GFkV, GFLV, GRSPaV and grapevine Pinot Gris virus in pot-grown grapevine cv. Shine Muscat plants, and viral disease symptoms in these plants were obviously attenuated. In addition, this extract significantly induced expression of pathogenesis-related protein genes and stimulated activity of antioxidant enzymes in grapevines. Taken together, these results indicate that the crude garlic extract acts as a significant inhibitor against a broad range of grapevine viruses.  相似文献   
54.
Root rot symptoms were observed in fields of alfalfa in Chifeng city, Inner Mongolia, China in 2016. Disease incidences of seven alfalfa varieties planted in 2014 ranged from 56% to 95%, while incidence of Gongnong No. 1 planted in 2016 was 8%, 31% and 76% in 2016, 2017 and 2018, respectively. Paraphoma isolates were consistently recovered from black necrotic root tissues of diseased plants with a frequency of 77.1%. Based on morphological characters and phylogenetic analysis of rDNA internal transcribed spacer (ITS), elongation factor 1-α (EF1-α) and β-tubulin (TUB), this fungus was identified as Paraphoma radicina. Glasshouse pathogenicity experiments showed that P. radicina significantly reduced above- and below-ground biomass of alfalfa plants 2 months after inoculation. Paraphoma radicina infected 70% of the plants inoculated with a root dip in conidia, and these symptoms were consistent with the symptoms in the field. Paraphoma radicina was successfully reisolated from disease roots of the inoculated alfalfa plants. This is the first report of P. radicina as the causal agent of alfalfa root rot in China.  相似文献   
55.
为明确不同品种甘薯茎尖培养的最佳NAA/6BA配比,设置0.1 mg/L/2.5 mg/L、0.2 mg/L/2.5 mg/L、0.2 mg/L/1.0 mg/L 3组NAA/6BA浓度配比处理,观测不同浓度激素处理对‘北京553’、‘红香蕉’、‘苏薯8号’、‘烟薯25’、‘安吉芋’、‘济徐23’、‘渝紫7号’、‘商薯19’茎尖培养成苗率、愈伤组织直径、不定根数目、叶片数和植株高度的影响,同时调查不同品种试管苗的移栽成活率。结果表明,‘红香蕉’、‘济徐23’、‘渝紫7号’、‘商薯19’在0.1 mg/L/2.5 mg/L的处理下培养效率最高;‘安吉芋’在0.2 mg/L/2.5 mg/L的处理下培养效率最高;‘苏薯8号’、‘北京553’、‘烟薯25’在0.2 mg/L/1.0 mg/L的处理下培养效率最高。因此,在甘薯茎尖培养过程中,不同甘薯品种适宜的NAA/6BA配比存在显著差异,在实际生产中应根据品种特性来进行调整激素的用量和比例。  相似文献   
56.
陆秀娟  李祥栋  石明  潘虹  魏心元  陆平  苏跃 《种子》2020,(1):33-35,41
为研究薏苡紫色柱头性状的遗传规律,利用4份材料做亲本构建4个杂交组合,观察并记录其F 1、F 2植株的性状特征和分离比例。结果显示,紫色柱头相对于白色为显性,各F 2群体植株的柱头颜色分离比皆符合3∶1比例,说明紫色柱头是由1对显性等位基因控制。  相似文献   
57.
DNA去甲基化酶(dMTase)是主动去甲基化过程中具有糖基化酶和脱嘌呤裂合酶活性的双功能酶.基于茶树基因组数据,本研究利用生物信息学方法对茶树DNA去甲基化酶(CsdMTase)编码基因进行了全面鉴定和序列分析.全基因组鉴定结果表明,舒茶早基因组中包含4个CsdMTases,系统进化分析将CsdMTases分为DME...  相似文献   
58.
In this study, melatonin (MEL)-mediated plant resistance to tobacco mosaic virus (TMV) was examined to study local infection in Nicotiana glutinosa and systemic infection in Solanum lycopersicum. Exogenous application of 100 µm MEL increased anti-virus infection activity to 37.4% in virus-infected N. glutinosa plants. The same treatment significantly reduced relative levels of virus RNA analysed by qRT-PCR and virus titres measured by dot-ELISA, and increased the relative expression levels of the PR1 and PR5 genes analysed by qRT-PCR, in virus-infected S. lycopersicum. MEL treatment induced considerable accumulations of salicylic acid (SA) and nitric oxide (NO) but did not significantly affect production of hydrogen peroxide (H2O2) in the virus-infected S. lycopersicum plants. Transgenic nahG N. tabacum was used to determine whether MEL-induced TMV resistance was dependent on the SA pathway. The results showed that the relative RNA level of the TMV analysed by qRT-PCR and virus titres analysed by dot-ELISA were not reduced by the MEL treatment in the nahG transgenic N. tabacum seedlings treated twice with 100 µm MEL. The increased relative expression levels of PR1 and PR5 were greatly reduced when cPTIO, an NO scavenger, was included in the MEL treatment. A working model of MEL-mediated plant resistance to TMV is proposed. MEL-mediated plant resistance to viruses provides a new avenue to control plant viral diseases.  相似文献   
59.
60.
Y Wang  Z W Fan  Y D Shen  X X Li  Y Liu  Q Q Huang 《Weed Research》2019,59(6):419-426
Invasive plants may be more plastic than non‐invasive plants and maintain high fitness under various environmental conditions. Previous studies mainly focused on the comparisons between invasive and native plants, and comparisons between highly invasive and less invasive exotic species are still relatively rare, especially for comparisons at the subspecies level. This study examined the effects of nutrient addition and shading on the performance of the highly invasive Mimosa invisa and its less invasive subspecies M. invisa var. inermis under either isolated or competitive conditions. Nutrient addition increased biomass and plant height and decreased root‐to‐shoot ratio (R/S). Shading decreased biomass and R/S and increased plant height. Under isolated conditions, the two invaders did not differ in R/S, plant height and plasticity of these traits in response to nutrient addition or shading, and the two invaders also did not differ in biomass production under each of the nutrient and light treatments. When the two invaders competed with each other, M. invisa outcompeted M. invisa var. inermis under high soil nutrient conditions, and the two invaders did not differ in performance under other growth conditions. Thus, only considering competition may we find out the difference between highly invasive species and their closely related, less invasive subspecies. Management of M. invisa should focus on habitats with high soil nutrient availability, in which M. invisa is more likely to dominate.  相似文献   
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