Root exudation of prometryn and its metabolites from Chinese celery (Apium graveolens)

Root exudates from Chinese celery (Apium graveolens) and Chinese cabbage (pak choi, Brassica chinensis) plants treated by prometryn, an herbicide, were qualitatively and quantitatively investigated and compared under hydroponic cultivation. Prometryn and its metabolites released into the nutrient solution were analyzed by ultra-performance liquid chromatograph coupled with orbitrap mass spectrometer to investigate whether this xylem-mobile herbicide is exuded from the roots. The results showed that celery and pak choi had different root exudation profiles. Celery metabolized prometryn to prometryn sulfoxide and released both compounds from the roots. In contrast, pak choi barely metabolized or actively released prometryn from the roots. The concentration of prometryn sulfoxide released from celery after 96 hr was 21 µg/L, which was nearly one-third that of released prometryn. Our results indicate that the root exudation and translocation of xylem-mobile herbicides could be significant in plants and are highly species dependent compared with phloem-mobile herbicides.     

17份食用向日葵杂交种苗期抗旱性综合评价

以17份食葵杂交种为试材,采用1/2 Hoagland营养液水培的方式,以PEG-6000模拟干旱,分析苗期根系形态和生物量对干旱胁迫的响应,并对食葵杂交种的抗旱能力进行综合评价.结果表明:苗期食葵根系形态指标受干旱影响程度要高于生物量,根系形态各指标受干旱影响程度顺序为:根体积>根平均直径>根尖数>总根长>根表面积,...     

不同耐旱性玉米根系解剖结构比较研究

以大田生长的不同耐旱性玉米品种为试验材料,采用徒手切片法和常规石蜡制片法对玉米的初生根和各层次生根的基部、中部和根毛区显微结构进行了系统研究和比较.结果显示:与不酎旱品种玉米的根系相比,耐旱玉米的初生胚根的皮层细胞层数较少,木质部导管数量较多、导管直径较小;各层次生根的皮层细胞层教相对较少,木质部导管数量相对较多,导管直径相对较小.     

毛乌素沙地臭柏、油蒿细根生产动态及影响因子

在毛乌素沙地开发整治研究中心北试实验地选取了七块样地,并依据建群植被外貌特征划分为臭柏群落、臭柏灌丛、油蒿群落三类。用根钻对各样地一个生长季内的根系进行了五次取样,同时测量土壤水分、枝条生长长度、温湿度等一些气象因子。对活细根分级并称干重,发现臭柏、油蒿不同径级细根的季节动态不同,不同土层内相同径级的细根生产动态也不相同:①臭柏与油蒿D≤2 mm的细根生物量在4~5月份都有一个快速增长的阶段,随后增长格局各不相同。②臭柏灌丛中,1 mm相似文献   

南瓜饲养榕树粉蚧的发育历期与生物学特征初报

榕树粉蚧是一种重要的入侵害虫,对果蔬和园林植物存在巨大的潜在威胁.为满足开展检疫处理、防控、生物学和生理学等研究的需要,本研究以南瓜为饲养材料,在室温条件下(26±1℃,RH 65％±5％)观察榕树粉蚧的生物学特性与发育历期.结果 表明,榕树粉蚧具有典型的雌雄二型现象.雄虫主要经历卵、1～2龄若虫、预蛹、蛹、雄成虫阶段...     

生草栽培果园根系生长动态研究

通过对金太阳杏生草(紫花苜蓿)栽培与生长动态的研究表明,金太阳杏新根在1年中有2次明显的生长高峰,1次是在3～4月,占全年的37%以上,第二次在6月中下旬至7月上旬。而紫花苜蓿主要在7月中旬以后,两者在时间尺度也存在有差异,根据金太阳杏新根周年变化特点,掌握2个时期,即3月中旬和6月上中旬。     

植物根系对土壤团聚体形成作用机制研究回顾

土壤团聚体是土壤结构的基本单元,土壤水力侵蚀的微观描述即为土壤团聚体的破裂过程。研究表明:植物根系可以改变土壤的力学以及水文特征,促进土壤团聚体的形成和稳定。因此,对近20年国内外的相关研究成果进行较为系统的回顾,从根系对土壤团聚体的物理、生物、电化学作用3个研究视角,分析了植物根系对土壤团聚体形成的作用机制,提出了现有研究中存在的问题及研究趋势,这对深入认识植物根系对土壤团聚体的影响及其作用机制、发展根-土相互作用的土壤侵蚀过程模型具有重要的意义。     

Modern wheat cultivars have greater root nitrogen uptake efficiency than old cultivars

The availability of nitrogen (N) contained in crop residues for a following crop may vary with cultivar, depending on root traits and the interaction between roots and soil. We used a pot experiment to investigate the effects of six spring wheat (Triticum aestivum L.) cultivars (three old varieties introduced before mid last century and three modern varieties) and N fertilization on the ability of wheat to acquire N from maize (Zea mays L.) straw added to soil. Wheat was grown in a soil where ¹⁵N‐labeled maize straw had been incorporated with or without N fertilization. Higher grain yield in three modern and one old cultivar was ascribed to preferred allocation of photosynthate to aboveground plant parts and from vegetative organs to grains. Root biomass, root length density and root surface area were all smaller in modern than in old cultivars at both anthesis and maturity. Root mean diameter was generally similar between modern and old cultivars at anthesis but was greater in modern than in old cultivars at maturity. There were cultivar differences in N uptake from incorporated maize straw and the other N sources (soil and fertilizer). However, these differences were not related to variation in the measured root parameters among the six cultivars. At anthesis, total N uptake efficiencies by roots (total N uptake per root weight or root length) were greater in modern than in old cultivars within each fertilization level. At maturity, averaged over fertilization levels, the total N uptake efficiencies by roots were 292?336 mg N g^?1 roots or 3.2?4.0 mg N m^?1 roots for three modern cultivars, in contrast to 132?213 mg N g^?1 roots or 0.93?1.6 mg N m^?1 roots for three old cultivars. Fertilization enhanced the utilization of N from maize straw by all cultivars, but root N uptake efficiencies were less affected. We concluded that modern spring wheat cultivars had higher root N uptake efficiency than old cultivars.     

植物根系对土壤水力参数影响的定量研究综述

植物根系是土壤结构以及土壤水力参数变化的重要影响要素。目前不仅缺乏定量描述“根-孔隙-土壤水力参数”相互作用的研究方法,在更大尺度上根系作用的客观表达也尚不明确,由此导致降雨入渗、径流和蒸发等流域水文过程的精细刻画与模拟预测具有很大的不确定性。基于文献检索,本文对国内外相关研究进行了回顾与梳理,量化了植物根系对土壤水力参数的改变和影响,并提出其与植被、土壤类型的响应方式,总结了植物根系动态性生长下的土壤水力参数定量表述及其预测模型进展。同时分析了在定量研究根-土复合系统中存在的问题及未来研究的发展方向,指出目前根系影响土壤水力参数的研究主要集中在小尺度控制实验方面,忽略了大尺度下土壤空间异质性及外部环境因素的干扰,强调大尺度根系作用和根系参数纳入土壤结构的重要性和实际意义,进一步与水文模型的深度耦合逐渐成为未来研究的热点。     

Effect of Arbuscular Mycorrhizal Fungi and Phosphate-Solubilizing Bacteria Consortia Associated with Phospho-Compost on Phosphorus Solubilization and Growth of Tomato Seedlings (Solanum lycopersicum L.)

ABSTRACT

The exploitation of phosphate mines generates an important quantity of phosphate sludge that remains accumulated and not valorized. In this context, composting with organic matter and rhizospheric microorganisms offers an interesting alternative and that is more sustainable for agriculture. This work aims to investigate the synergetic effect of arbuscular mycorrhizal fungi (AMF), phosphate-solubilizing bacteria (PSB) and phospho-compost (PC), produced from phosphate-laundered sludge and organic wastes, and their combination on plant growth, phosphorus solubilization and phosphatase activities (alkaline and acid). Inoculated mycorrhizae and bacteria strains used in this study were selected from plant rhizosphere grown on phosphate-laundered sludge. Significant (p < .05) increases in plant growth was observed when inoculated with both consortia and PC (PC+ PSB+ AMF) similar to those recorded in plants amended with chemical fertilizer. Tripartite inoculated tomato had a significantly (p < .05) higher shoot height; shoot and root dry weight, root colonization and available P content, than the control. Co-inoculation with PC and AMF greatly increased alkaline phosphatase activity and the rate of mycorrhizal intensity. We conclude that PC and endophytic AMF and PSB consortia contribute to a tripartite inoculation in tomato seedlings and are coordinately involved in plant growth and phosphorus solubilization. These results open up promising prospects for using formulate phospho-compost enriched with phosphorus-solubilizing microorganisms (PSM) in crop cultivation as biofertilizers to solve problems of phosphate-laundered sludge accumulation.