人参光生理研究进展

本文介绍了国内外有关人参光合作用最适光强、光饱和点和补偿点、主要生态因子和不同光质对人参生长发育、有效成分积累影响等方面研究进展,为人参生产中改善供光条件提供依据.人参是五加科多年生草本阴性植物,要求在遮荫条件下栽培,遮荫方式不同,左右光照条件直接影响人参生育和产量.光是光合作用的能源,植物的全部产品,直接或间接来源于光合作用.光合能力的大小,对植物经济产量或生物产量的形成关系极大.因此,探讨光与人参生长发育的关系,对提高人参产量和质量意义重大.本文就有关人参光生理的研究近况加以概述.     

重金属对水稻生长发育和产量影响的研究进展

本文综述了重金属对水稻生长发育和产量形成的影响及表现,其中:重金属元素对水稻生长发育的影响,在不同生育期、不同器官和品种类型之间均存在差异;对水稻产量形成产生的影响,主要表现在单位面积穗数、每穗颖花数、结实率和千粒质量等方面。同时对水稻田重金属污染的治理进行了讨论,并从重金属积累的分子机理、土壤重金属有效态的降低以及培育重金属低积累的水稻新品种3个方面提出了相应的建议。     

青蒿素对植物化感效应研究进展

青蒿素是一种由部分蒿属植物产生的倍半萜内酯,是一种有效的抗疟疾药物,对癌症、肝炎和血吸虫病等均有疗效。植物化感作用是植物(含微生物)通过释放化学物质到环境中对其它植物产生的直接或间接的有害作用。综述了青蒿素的合成、影响青蒿素化感效应的因素及释放途径、青蒿素对土壤成分及植物生长的影响等方面的研究成果,并指出了进一步的研究方向。     

腐殖酸对高粱干物质产量的影响

据报道,腐殖酸直接和间接地影响着植株生长。腐殖复合物通过改良土壤物理、化学和生物等条件而间接生效;通过增加植株叶绿素含量、加速呼吸作用,促进荷尔蒙生长反应、改良植物膜透性,或者通过这些过程的综合作用而直接影响植物生长。有人还发现,腐殖复合物影响植株的千物质生产和养分吸收。本研     

茶树新梢水势变化规律的探讨

自从Slatyer和Taylor(1960)在植物生理界引入水的势能概念以后,水势作为植株体内水分状况的基本度量方法已获得广泛的承认。在土壤—茶树—大气连续系统中,水势是决定水分运动的重要因素,并直接影响茶树体内许多生理性状的表现,当茶树出现缺水时,新梢水势很快下降,进而影响茶树的生长发育和各种生理过程。因此,     

水稻根系生长发育特性及其与产量形成的关系

根系是植物与土壤进行物质交换和信息交流的桥梁,对植物的生长和发育具有至关重要的作用。水稻根系的状况直接影响着地上部分的生长发育以及产量的形成,是制约着高产水稻产量潜力进一步发挥的关键因素。本文从根系形态建成、活力功能、分子遗传几个角度对水稻根系的形态分布、营养元素吸收、物质合成和分泌等特性及其与产量形成的关系进行了综述,试图为促进根系研究,通过调控根系的生长发育来提高水稻产量提供参考。     

磷浓度处理对大豆根际土壤微生物群落结构的影响

根际土壤微生物是根际土壤生态系统的重要组成部分,与根际养分有效性、植物生长发育等关系密切.土壤磷素营养的差异可引起植物根系分泌物和根形态的变化,但对植物根际微生物的作用还少有报道.在盆栽条件下,研究了3种磷浓度处理对生长在黑土土壤上3个采样时期(v3、R1和R3期)的大豆根际微生物群落结构的影响.采用PCR-DGGE技术对细菌16S rDNA和真菌ITS片段进行解析,对DGGE图谱主成分分析(VCA).结果表明:大豆根际土壤细菌和真菌群落结构均随生育期而迁移,说明生育时期较磷浓度处理而言是影响根际微生物群落结构产生变化的主要因素;大豆根际真菌群落结构受不同磷浓度处理产生分异体现在v3期,细菌结构产生分异体现在v3和R1期,说明磷浓度处理对大豆根际微生物的影响主要表现在大豆生育的早期,随着生育时期的推进.这种差异弱化至不明显.     

根际pH对水稻细胞膜质子泵基因表达的影响

 通过水培试验研究了不同根际pH对水稻(日本晴)细胞膜质子泵基因表达的影响。以栽培在pH 5.5的营养液中的水稻作为对照,然后分别转移到pH 3.5和pH 7.5的营养液中培养。研究发现,质子泵基因OsPMA1、 OsPMA2、OsPMA3、OsPMA7在根系和叶片中均有表达;当营养液pH为3.5或7.5时,上述质子泵基因的表达总体上均比对照（pH 55）降低。但植物地上部的质子泵表达不受根际pH的影响。而且,pH越低,水稻生物量与体内的氮含量越低。其可能的原因是,水稻在pH骤然降为3.5的营养液中没有及时适应高浓度的H+胁迫,导致根系细胞膜质子泵受抑制,进而影响水稻对养分的吸收。而pH 7.5与植物细胞质pH相当,质子泵无需过量表达即可用于养分吸收。说明根际pH直接影响到根系细胞膜质子泵在转录水平上的表达,并间接影响根系对养分的吸收和植物的生长。     

植物磷匮乏下的根系、代谢和分子响应研究进展

磷是植物正常生长发育所必需的大量元素之一.由于多数土壤条件下可获得的有效磷不足,因此土壤中的磷会影响作物产量潜力的表现.了解植物对低磷胁迫或磷匮乏的响应机制是至关重要的,相关研究已经取得一系列的进展.本文回顾了植物磷匮乏条件下根系统的响应,因为外部土壤中磷的供应状态会影响根构型,评述了植物激素和磷酸酶对磷匮乏的响应,并...     

有机种植方式对茶园土壤酸碱度的影响

土壤过度酸化是影响茶产业持续健康发展的主要因素之一,为了解有机管理方式对茶园土壤酸碱度的长期影响,以常规茶园为对照,研究了我国18个省份84个产茶县有机管理1～21 a对茶园土壤pH的影响。结果表明,有机茶园比常规茶园土壤pH平均高0.36,达极显著水平;随着有机管理年份的增加,茶园土壤pH总体为先显著上升、后显著下降并维持相对平稳,有机管理1～5、6～10、11～15、16～21 a的pH比常规茶园分别高0.48、0.23、0.28和0.30,均达显著或极显著水平;有机管理方式还有利于土壤pH向最适合茶树生长发育的方向发展,pH 4.5～5.5的茶园占比,常规茶园为41.9%,有机管理1～5、6～10、11～15、16～21 a的茶园分别为53.1%、48.9%、58.7%和66.7%,总体随有机管理年限的增加而增加。可见,有机管理方式能防止茶园土壤严重酸化,使土壤pH向着最适合茶树生长发育的方向发展。     

Grazing and fertilization influence plant species richness via direct and indirect pathways in an alpine meadow of the eastern Tibetan Plateau

Grazing and fertilization influence plant species richness through multiple pathways, but the exact pathways and their relative contributions are unclear. Here, we report on a 3‐year field experiment on an alpine meadow in which we manipulated grazing and fertilization simultaneously to assess their direct and indirect effects on plant species richness. Results indicated that both grazing and fertilization significantly influenced plant species richness via above‐ and belowground pathways. Specifically, the direct effect of grazing (?0·30, effect size) on species richness was negative, mainly due to selective feeding. This was comparable, in magnitude, to a positive indirect effect of grazing (0·36) on species richness, due to decreased aboveground biomass and increased belowground biomass. The direct effect of fertilization (?0·34) on species richness was negative, which was attributed to the changes of soil pH and available nitrogen; this effect was double the indirect effect (?0·16), which largely stemmed from the increased aboveground biomass rather than changes in belowground biomass. No significant interaction of grazing and fertilization on species richness was observed, but the effect of fertilization on species richness was masked by the effect of grazing in the combined treatment. It was concluded that moderate nitrogen addition (<51·0 kg N ha^?1 year^?1) could increase local pasture productivity while also sustaining species richness stability.     

Nutrient deficiency and hypoxia as constraints to Panicum coloratum growth in alkaline soils

Alkaline and saline–alkaline soils impose severe restrictions on plant growth. Panicum coloratum var. coloratum is a perennial C4 forage grass widely used in tropical and subtropical environments. Published information on its responses to alkaline soil conditions is scarce. The objectives of this study were (i) to characterize the effects of alkaline substrates on germination and initial growth in this species, (ii) to assess the influence of high pH in combination with reduced availability of either nutrients or oxygen and salinity, on plant growth and (iii) to evaluate some physiological traits potentially responsible for growth restrictions under alkaline soil conditions. Trials were conducted in a greenhouse. Germination and early plant survival were not affected by alkalinity. To isolate the effects of high pH, reduced nutrient and oxygen availability on growth, plants were grown either in neutral or alkaline soil, in hydroponics, in neutralized alkaline soil (with or without supplementary fertilization), or were flooded to induce hypoxia. Alkalinity effects on growth in hydroponics were milder than in soil. Growth in alkaline soil with nutrient supplement was still significantly lower (by 40%) than in neutral soil. Both alkalinity and hypoxia reduced growth non‐synergistically. These results show that studies of plant response to alkaline substrates carried out in aerated nutrient solutions can only partially address the complexity of this stress. Photosynthesis and PSII activity were among the physiological mechanisms negatively affected by alkalinity and may be partially responsible for the growth limitations observed in P. coloratum under alkaline conditions.     

刚果12号桉叶片水抽提物对4种植物幼苗生长的影响

采用盆栽法研究了刚果12号桉叶片水抽提物在水分胁迫（水渍与干旱）和养分缺乏与丰足的环境条件下对4种植物生长的影响。结果表明，植物种类与盆栽基质的肥力是影响植物幼苗生长的关键因素，而桉叶水抽提物与土壤水分对植物幼苗的生长虽有影响，但与前二相比作用较小。因此，在退化的桉树人工林地重建林下植被，首先应选择耐瘠薄、耐旱性强和对化感作用不敏感的植物，如柱花草等豆科植物，既能自身固氮，又能通过循环增加土壤养分，当然应该注意豆科与禾本科搭配。结果还表明，在逆境条件下，桉树的化感作用会增强，并与其它因素互相作用，抑制林下植被生长。     

土壤pH值对茶树生长及矿质元素吸收的影响

采用盆栽法,研究了土壤不同 pH 值对茶树生长、茶叶品质成分含量和矿质营养元素吸收的影响。结果表明:茶树生长的最适 pH 是5.0—6.0,最佳 pH 值为5.5。在土壤 pH 5.5条件下,茶叶中水浸出物含量最高,氨基酸、茶多酚和咖啡碱含量也较高。茶树对矿质元素铝、锰、钙、钼、硼的吸收也以 pH 5.0—6.0最为有利。因此,茶园土壤的最适 pH 应是5.0—6.0,最佳 pH值为5.5,但在该 pH 范围内要注意增加锌肥的施用。     

Effects of straw retention and phosphorous fertilizer application on available phosphorus content in the soil solution during rice growth

Phosphorus (P) is an essential nutrient for proper rice growth, and available P in the soil solution is a direct source of P for rice uptake. In this study, a field experiment (experiment A: straw retention (SRT) treatment versus straw removal (SRM) treatment) exposed to 3 years of continuous SRT and a pot experiment (experiment B: five P levels; SRT and SRM treatments) with different concentrations of applied P fertilizer were conducted to study the effects of SRT and P fertilizer application on the available P concentration in the soil solution during rice growth and on rice yield. SRT decreased the available P concentration in the soil solution, although it did not alter the trend of available P concentration in the soil solution during plant growth. In addition, in the 10–20-day period after transplantation, the available P concentration in the soil solution was high, although it decreased thereafter. The available P concentration in the soil solution increased with the amount of applied P fertilizer, and the rice yield also increased with increasing applications of P fertilizer. The results of experiments A and B showed that SRT had no significant impact on the rice yield; however, continuous observations over a number of years are required to verify the results.     

Root deterioration in the potato early dying syndrome: Causes and effects of root biomass reductions associated with colonization byVerticillium dahliae

Russet Burbank potatoes were grown in the greenhouse in a split-root culture system to assess the impact of pathogens associated with the Potato Early Dying Syndrome (PED) on root deterioration. Plants were grown with all, half, or none of the root system in steamed soil infested withVerticillium dahliae, or in field soil infested withV. dahliae and other PED pathogens. The direct impact of pathogens on root deterioration versus indirect effects resulting from premature senescence of the whole plant was evaluated. Root biomass did not differ significantly between root halves from the same plant in infested and uninfested soil. Root biomass from plants with both halves of the root system in uninfested soil was usually greater than from plants with one or both halves growing in infested soil. Root biomass decreased rapidly after plant stems were inoculated with conidial suspensions ofV. dahliae. Root deterioration in PED was associated with premature senescence of foliar tissue and occurred independently of root colonization by root-colonizing pathogens.     

玉米秸秆还田对土壤理化性状与小麦生长发育和产量的影响研究进展

为给玉米秸秆还田技术的机理研究和推广应用提供参考,总结和分析了该技术的研究进展。秸秆还田对土壤物理性状、土壤水分含量、土壤有机质和矿质营养含量、土壤微生物和土壤酶活性,以及下茬小麦生长发育、产量及其构成因素、籽粒品质及麦田病虫害均有影响。未来该技术应增强增产机理、量化技术及配套技术方面的研究。     

Properties and Applications of an Organic Fertilizer Inoculated with Effective Microorganisms

Summary

Research studies were conducted to elucidate the chemical, physical and microbiological properties of an organic fertilizer that was inoculated and fermented with a microbial inoculant (Effective Microorganisms or EM). The quality estimation methods employed addressed the mechanistic basis for beneficial effects of soil improvement and crop yield. Effective Microorganisms or EM was utilized as the microbial inoculant that is a mixed culture of beneficial microorganisms. Tests showed that the fermented organic fertilizer contained large populations of propagated Lactobacillus spp. Actinomycetes, photo-synthetic bacteria and yeasts; high concentrations of intermediate compounds such as organic acids and amino acids; 0.1% of mineral nitrogen mainly in the ammonium (NH₄ ⁺) form, and 1.0% of available phosphorus; and a C:N ratio of 10. The quality of the fermented organic fertilizer depends on the initial water content; addition of molasses as a carbon and energy source; and the microbial inoculant. The medium pH appears to be reliable fermentation quality criterion for producing this organic fertilizer. Beneficial effects of the fermented organic fertilizer on soil fertility and crop growth will likely depend upon the organic fraction, direct effects of the introduced microorganisms, and indirect effects of microbially-synthesized metabolites (e.g., phytohormones and growth regulators).     

解磷细菌 Burkholderia 的分离鉴定及对香草兰生长和 P 吸收 的影响

香草兰为喜磷作物，从香草兰种植园中分离筛选到一株解磷微生物——伯克霍尔德氏菌 V-29。在 NBRIP 液体 培养基中摇床振荡培养 5 d 后可溶性磷含量达 475.3 μg/mL，培养基 pH 下降。通过大田试验研究了接种绿色荧光蛋白 标记后的解磷菌株 V-29 及其与有机肥发酵制得的微生物有机肥对香草兰生长和磷素吸收的影响。结果表明：单独接种 V-29 或施用微生物有机肥可显著增加香草兰植株干重、土壤有效磷含量；移栽 4 个月后，标记菌株 V-29 在香草兰根际 土壤中的含量可达 106 cfu/g 土壤。由此可见，伯克霍尔德氏菌 V-29 可单独作为生物菌剂或与有机肥发酵制得微生物有 机肥后用于农业生产中，以减少化肥施用量。