Subjects: Biology >> Botany submitted time 2023-01-30 Cooperative journals: 《广西植物》
Abstract：
Panax notoginseng (Burk.) F. H. Chen is a valuable Chinese herb in China, and the root should be harvested between three and seven years after planting it. However, the growth of P. notoginseng is frequently hindered due to replanting failure. There have been numerous studies proving that the accumulation of allelochemicals in the soil is considered to be one of the reasons for the replanting failure of P. notoginseng. Biodegradation of allelochemical in soil has been shown to be an effective measure to alleviate continuous cropping obstacles, so screening allelochemical-degrading bacteria could provide biological resources for soil remediation. Based on this, this study adopted a research strategy of enrichment and domestication to isolate and screen saponin-degrading bacteria from the rhizosphere soil of P. notoginseng, which had been grown continuously for 3 years and more. Also, the highly active strains were identified by 16S rRNA gene analysis. In addition, the effect of highly active strain SC3 on degrading allelochemicals under different conditions was studied by HPLC. The results were as follows: (1) Eight strains of potentially degrading bacteria were successfully isolated from the rhizosphere soil of P. notoginseng. The results of the initial screening evaluation showed that strain SC3 had the best biodegradation effect on total saponins with 87.42% degradation rate. (2) Strain SC3 was identified as Stenotrophomonas sp. based on 16S rRNA gene analysis coupled with physiological and biochemical analyses. (3) The biodegradation of ginsenoside Rb1 by strain SC3 was stronger than its degradation of ginsenoside Rg1 under the same culture conditions. (4) The degradation of ginsenoside Rb1 by SC3 strain under liquid culture conditions was significantly affected by different factors, such as substrate concentration, inoculum amount and incubation temperature. This study shows that the enrichment and domestication strategy can effectively screen allelochemical-degrading bacteria, and a possible application of strain SC3 in the bioremediation of saponin contamination in agricultural environments.
Subjects: Biology >> Botany >> Applied botany submitted time 2020-09-15 Cooperative journals: 《广西植物》
Abstract：‘宝石1号’、‘晚香’和‘福晚８号’是2017年从福建省农业科学院果树研究所引进到广西南宁市的新品种（系）。为研究其在本地的生长发育和开花结果表现，以广西主栽品种：‘石硖’和‘桂明1号’为对照材料，研究其树体生长发育情况、产量、物候期、开花和落花落果规律及雌花开放数与温湿度的关系。结果表明：引进的3个龙眼新品种（系）高接后的植株长势和产量与‘石硖’相近，‘宝石1号’的单穗重最重，其次是‘福晚８号’，‘晚香’与2个主栽品种的相近；‘福晚８号’的果实成熟期最晚，生育期最长，达196 d，比‘桂明1号’长15 d。‘宝石1号’的花期最长，‘晚香’最短，3个新品种（系）的雌雄花开放顺序均为“雄~雌~雄~雌~雄”，‘宝石1号’和‘福晚８号’的雌雄花相遇时间较长，为18~19 d；3个龙眼新品种（系）在南宁均有3次落果高峰期，落果主要集中在6月份的第二次生理落果期。3个龙眼新品种（系）的雌花开放数与花前温湿度的关系密切，花期前后一定的温湿度范围内，较高的温度和较低的空气湿度有利于‘宝石1号’和‘福晚８号’的雌花开放，而较低的温度和较高的空气湿度有利于‘晚香’的雌花开放。综合来看，3个引进的福建龙眼新品种（系）在广西均能正常开花结果且表现较好，‘宝石1号’较早熟，‘福晚８号’成熟期最晚、雌雄花相遇时间长且落果率较低。
Subjects: Biology >> Botany >> Applied botany submitted time 2019-03-14 Cooperative journals: 《广西植物》
Abstract：青枯病是危害我国华南地区番茄生产最严重的土传性病害之一。为探讨在人工接种青枯菌条件下，两种不同砧木嫁接对番茄青枯病的抗性及根际微生物数量的影响。分别用砧木“番砧1号”和“茄砧21号”与樱桃番茄“粉贝贝”进行嫁接，采用稀释平板法对各嫁接组合的根际微生物进行分离。结果表明：采用抗病砧木嫁接显著提高了番茄的抗病性，降低了发病率和病情指数，延缓了发病时间。青枯菌在侵染植株过程中呈现动态变化，其数量从根系到地上茎部逐渐减少。砧穗嫁接植株、砧木自根嫁接植株根际基质和根系中的青枯菌数量降低，且地上茎部中的病原菌数量显著低于接穗自根嫁接植株。接种青枯菌后，各嫁接组合根际基质中的细菌、真菌和放线菌的数量随发病期的变化呈先增加后降低的趋势。采用抗病砧木嫁接总体上提高了植株根际微生物总量、细菌及放线菌的数量，降低了真菌的数量，改善了嫁接植株根际微环境，对降低番茄青枯病发病率具有重要作用。
Subjects: Biology >> Botany >> Applied botany submitted time 2019-02-25 Cooperative journals: 《广西植物》
Abstract：枯萎病是一种严重危害瓜类蔬菜生产的土传病害，嫁接栽培是防治瓜类枯萎病的有效方法。本研究砧用瓠瓜种质幼苗生长指标与抗病性的相关性，并对抗病杂种优势进行分析，为筛选具有优良抗病性的砧用瓠瓜种质和选育杂交组合提供理论依据。结果表明：砧用瓠瓜种质 H041 对西瓜枯萎病表现高抗（HR），对瓠瓜枯萎病表现抗病（R），种质 H01、H05 和杂交组合 H01×H041、H041×H05、H05×H041 对两种枯萎病均表现抗病（R）。砧用瓠瓜幼苗接种西瓜枯萎病菌后，病情指数与下胚轴粗度呈显著负相关；接种瓠瓜枯萎病菌后，总根长、根系表面积与病情指数呈极显著负相关，表明砧用瓠瓜对枯萎病的抗病性与根系生长具有相关性，可以根据根系生长情况快速评价砧用瓠瓜对瓠瓜枯萎病的抗性表现。分析砧用瓠瓜杂交组合的抗病性杂种优势显示，供试杂交组合 H05×H041 对西瓜枯萎病具备超中亲优势；杂交组合 H01×H041、H02×H041、对瓠瓜枯萎病抗性具有负向杂种优势。综合研究结果，砧用瓠瓜种质、H041、H05 兼抗西瓜枯萎病和瓠瓜枯萎病，且配制出的杂交组合表现抗性杂种优势，可作为选育抗两种枯萎病的砧木或栽培品种的抗源亲本，其中 H041 可作为优势骨干亲本。
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