两系杂交中籼皖稻153抗倒特性分析

[目的]揭示皖稻153抗倒特性强的成因。[方法]对两系杂交中籼皖稻153和其双亲及部分同型主栽组合等茎秆和根系性状进行测量和分析。[结果]皖稻153较之其他参试品种,在茎秆性状上具有适中的株高和较强的抗折力;在根系性状上具有丰富的根系数量和明显的根长优势。[结论]皖稻153表现出较小的倒伏指数和较强的抗倒能力。     

耕作方式对小麦抗氧化酶和产量的影响

通过田间试验研究耕作方式对小麦根系、叶片抗氧化酶和产量的影响。试验设置耕翻+镇压（HS）、旋耕+镇压（RS）和旋耕（R）3个处理。结果表明,在拔节期、孕穗期和花后10 d HS处理叶片和根系超氧化物歧化酶（SOD）活性均显著高于其他2个耕作处理;在拔节期、抽穗期和花后5 d HS处理根系过氧化物酶（POD）活性均显著高于RS和R处理;在越冬期、孕穗期至花后5 d,HS处理叶片过氧化氢酶（CAT）活性均显著高于RS和R处理;除拔节期和孕穗期,HS处理叶片丙二醛（MDA）含量均显著低于RS和R处理。相关分析表明小麦产量和叶片CAT活性呈极显著正相关性（R=0.930,P＜0.01）,与叶片MDA含量呈显著负相关（R=-0.774,P＜0.05）。HS处理可以通过提高小麦有效穗数、穗粒数和千粒重从而提高产量,产量分别比RS和R处理高出5%和8%。综上表明,耕翻+镇压可提高小麦根系和叶片抗氧化酶活性,降低叶片MDA含量,延长小麦灌浆期实现小麦高产。     

浑河源头不同水源涵养林根系分布特征

【目的】揭示浑河源头不同水源涵养林根系分布特征。【方法】采用根钻法和WinRHIZO根系分析系统等研究手段,定量分析了不同林地根系参数(根质量密度、根长密度、根表面积密度、根体积密度)垂直分布特征以及不同径级根系分布特征。【结果】各个样地植物根系主要集中在0～20 cm土层,且随着土层深度的增加而减小,0～10 cm土层红松林地和采伐迹地显著大于混交林地和落叶松(p<0.05);各样地不同径级根质量密度分布存在差异,多为细根,根质量密度在0.47～9.73 g/cm~3之间,根长密度在0.88～5.90 cm/cm~3之间,根表面积在0.22～0.94 cm2/cm~3之间,根体积密度在0.003～0.022 cm~3/cm~3之间。【结论】不同水源涵养林植物根系主要集中在0～20 cm,红松和混交林地根系量最高。     

No “Gadgil effect”: Temperate tree roots and soil lithology are effective predictors of wood decomposition

The “Gadgil effect” hypothesizes that root associations may slow down decomposition through pre‐emptive competition. In the context of recalcitrant litter decomposition, specifically coarse wood debris, it is uncertain as to what is the relative importance of soil communities associated with living roots when compared to those without roots. Here, it is hypothesized that the presence of live roots and active photosynthates will enhance wood decomposition. To test this hypothesis, the presence or absence of temperate tree roots was used in this study. Sugar maple (Acer saccharum) and white oak (Quercus alba) roots were manipulated at three sites of either limestone or shale parent rock residuum. At each site, wood substrate was placed in soils beneath the canopy of either A. saccharum or Q. alba, while in the presence of roots (root⁺). At the same time, wood substrate was placed in the same soil community, but live root exposure was eliminated by trenching (root^?). This eliminated active photosynthate supply to the soil microbial community. Results determined that live root exposure promoted faster decomposition and greater mycelial colonization of wood substrate. Also, sites of shale parent rock residuum had higher rates of decomposition in comparison with limestone parent rock residuum. Although additional work is needed to determine the extent in which roots and lithology can facilitate wood decomposition, these findings suggest that living roots impact decomposers and provide a pathway towards humus and soil organic matter formation.     

茶树根系跨膜吸收氟的生理与分子机制

茶树[Camellia sinensis(L.)O.Kuntze]是高富集氟的植物,氟在叶片中被大量累积。饮茶是人们摄取氟的重要途径,氟的过量摄入会影响人体健康。茶树主要通过根系从土壤中吸收富集氟,但是根系跨膜吸收氟的生理与分子机制尚不清楚。本文综述了茶树根系吸收氟的主动和被动途径,总结根系H+-ATPase和Ca^2+-ATPase介导氟的跨膜主动吸收过程与分子机制;剖析离子通道和Al-F络合在根系被动吸收氟过程中的作用及微观过程;分析影响根系吸收富集氟的主要因素及其调控措施。提出通过研究茶树根系氟跨膜吸收相关转运蛋白及其相关基因的克隆、表达和功能验证,以揭示跨膜吸收氟的分子机制;进而研究调控根系对氟的选择吸收,以保障茶叶质量安全和饮茶健康。     

紫色土丘陵区生物埂不同植被类型土壤分离水动力学特征

野外采集紫色土区六棱型预制网格式护坡生物埂内不同植被类型原状土样,通过室内模拟细沟水槽(长4 m,宽0.12 m,深0.1 m)冲刷试验,探究不同植被类型影响下土壤分离能力与水动力学参数之间的关系。选择麦冬、韭菜2种生物埂类型,以单一网格式裸坡为对照,在3个坡度(15°,20°,25°)、5个流量(39.86,59.98,79.67,100.45,121.16 L/min)组合条件下进行冲刷试验。结果表明:生物埂内不同植被类型下土壤分离能力差异显著(P0.05),表现为麦冬(均值2.24 kg/(s·m~2))对照(均值1.34 kg/(s·m~2))韭菜(均值1.09 kg/(s·m~2))。幂函数方程可用于描述土壤分离能力与水流剪切力(R~2=0.75)、水流功率(R~2=0.73)、单位水流功率(R~2=0.46)及过水断面单位能量(R~2=0.63)间的数学关系。生物埂各植被类型下土壤发生分离的临界剪切力τ_c表现为τ_c麦冬(8.75 Pa)τ_c韭菜(6.47 Pa)τ_c对照(1.93 Pa),表明植被可增强网格式护坡生物埂土壤抵抗分离的能力。     

三种常用方法防治松干线虫的研究

在病虫害防治过程中切断传染路径是重要的传统防治方法。松干线虫的主要传染媒介是松墨天牛,伐除病死木、熏蒸方法处理残余伐根、诱捕器捕杀天牛成虫3种方法相结合,处理染病林分,并和没有进行处理的林分进行比较,试验表明,染病个体植株数明显下降,松墨天牛虫口密度大幅度降低。基于这样的思路,设计了试验方案,收集大量数据,并进行数据处理分析,得出结论,为松干线虫的防治提供理论依据。     

A simple method to obtain endophytic microorganisms from field-collected roots

We describe a simple technique for obtaining endophytic microorganisms from field-collected roots. Roots of plant species were surfaced-sterilized, cut into pieces, and then each root piece was transferred to drops of Gel-Gro medium. The number of segments with bacteria and fungi was quantified and those with bacteria and dark septate endophytic (DSE) fungi were plated onto tryptic soy agar (TSA) and malt extract agar (MEA), respectively. When arbuscular mycorrhizal fungi (AMF) grew from root segments, they were inoculated into Ri T-DNA-transformed carrot root cultures. Eight different species of bacteria and five dark septate endophytes were isolated. Thirty AMF isolates were identified and continuous pure cultures established. This easy and inexpensive approach allowed us to culture various endophytic microorganisms in an in vitro system saving time and space.