植物矿质营养的生态意义：Ⅱ.植物对矿质养分的吸收,利用和分配

阐述了植物对矿质养分的吸收，植物相对生长率与奢侈吸收；养分的分配与利用效率；养分的储藏与损失方面的研究进展。     

VA菌根吸收矿质养分的机制

阐述了ＶＡ菌根对不同形态磷的吸收机制；提出了“菌丝际”的新概念；以及菌根与植物氮素营养和其它养分元素吸收的关系。     

植物矿质养分吸收的长距离反馈调节研究进展

植物的养分吸收能力受到局部信号和冠-根长距离反馈信号的共同调节。近年局部调节系统的研究进展较快,长距离反馈调节的研究则相对薄弱。本文从养分吸收反馈调节现象的普遍性、 反馈信号的作用模式（促进/抑制）、 反馈信号的鉴定、 反馈信号的作用靶标等方面对该领域研究现状进行了综述,并提出了有待进一步深入研究的问题。     

植物根系对养分缺乏和毒害的适应及其与养分吸收效率的关系

根系是植物对养分最敏感的部位,直接与养分接触,参与养分的吸收过程,在养分胁迫(缺乏或毒害)下最先引起反应。植物在低氮、低磷、低钾和元素中毒胁迫下,其形态和生理上都发生一定的变化。综述了养分缺乏和元素毒害胁迫下植物根系形态的变化、生理反应、分子生物学基础及其与养分吸收效率和对元素毒害的抗性的关系。     

细胞膜H+-ATP酶在植物矿质营养中的作用

细胞膜H+-ATP酶是植物体内一类重要的质子泵,也是一种极其关键的转运蛋白,在植物各种生命活动中具有重要的功能。本文综述了细胞膜H+-ATP酶的活性调控机制,及其在植物根系吸收与利用矿质营养中的生理作用。细胞膜H+-ATP酶通过消耗ATP将细胞质中的H+排出,为养分离子的跨膜转运,以及有机酸和生物硝化抑制剂等物质的分泌提供细胞膜电位和质子驱动力。在缺磷、缺铁和铝毒等营养逆境下,细胞膜H+-ATP酶在受诱导后通过分泌H+使根际酸化,从而提高磷和铁的有效性,还通过促进有机酸分泌来活化土壤中的矿物态磷,并且可以降低铝离子的毒害。此外,细胞膜H+-ATP酶还参与调节植物根系的生长以及植物与丛枝菌根真菌的共生。通过遗传途径调节细胞膜H+-ATP酶及其上游调节因子,如蛋白激酶和磷酸酶等基因的表达,以及对细胞膜H+-ATP酶的特定氨基酸位点进行突变,可以改良作物细胞膜H+-ATP酶的活性。这是一种提高作物养分利用效率、增强作物抵抗营养逆境的有效策略。     

等高固氮植物篱模式对坡耕地土壤养分的影响

对坡耕地土壤剖面养分的研究结果表明，等高固N植物篱模式对养分的影响表现在对养分的归还和在土壤剖面的再分配。培植植物篱5年后，该系统中与植物篱不同距离位点0－40cm土层土壤有机质和全N含量分别比对照高1.2-2.3倍和0．5－0．7倍，有效磷和速效钾显著增加，表明植物篱可有效改善土壤养分状况。研究结果还表明在植物篱模式下0－60cm土层土壤有机质和全N含量均比种植带相应土层高，0－20cm土层有效磷和有效钾含量明显比种植带各位点相应土层高，表明植物篱与农作物之间无养分竞争；种植带下部0－40cm土层养分状况比种植带中部和上部相应土层优越，种植带上部各土层养分状况最佳；植物篱内40cm以下土层中有效磷和速效钾含量比种植带下相同土层低，说明植物篱根系可将土壤深层的P、K吸收并通过刈割枝叶返还种植带，发挥养分泵的功能。因此，植物篱通过生物固N和养分泵的功能提高种植带上层土壤养分含量和促进矿物养分循环。     

WRKY转录因子调控植物养分吸收利用及重金属解毒的研究进展

WRKY蛋白是植物特有的一类重要转录调控因子，它们通过与下游基因启动子上的W-box元件特异性结合诱导或抑制相关基因的表达，从而调控植物生长发育以及植物对生物和非生物胁迫的响应。植物WRKY基因组数目多，在拟南芥、大豆和水稻基因组中已经分别鉴定出74、182和109个，在植物对干旱、盐害、高温、养分匮乏和病原体感染等各种生物、非生物胁迫的响应过程中起关键作用。例如AtWRKY45和AtWRKY75参与调控拟南芥应答低磷养分胁迫，GmWRKY142正向调控拟南芥对镉胁迫的耐受性。在植物面对逆境胁迫时，WRKY蛋白通过与养分相关基因启动子的W-box元件特异性结合，进而实现自我调节或交叉调节，激活或抑制下游基因的转录以应对各种逆境胁迫。众多WRKY下游靶基因也已被鉴定出来，例如PHT家族成员与磷营养相关；3个拟南芥WRKY基因和6个大豆WRKY基因参与调控植物对氮素的吸收利用；6个拟南芥WRKY基因、10个大豆WRKY基因和5个水稻WRKY基因调节植物应对低磷胁迫；2个拟南芥WRKY基因和6个大豆WRKY基因影响植物对钾的吸收利用；3个大豆WRKY基因参与调控植物对硫营养的吸收利用；1个拟...     

丛枝菌根(AM)真菌与共生植物物质交换研究进展

丛枝菌根(Arbuscular Mycorrhizal,AM)真菌能与约 80% 的陆生植物形成共生关系,植、 菌间矿质养分、 碳水化合物的物质交换是自然界物质循环的重要内容。目前,AM 真菌促进共生植物矿质养分吸收的研究相对较多。研究表明, AM 真菌可通过根外菌丝更小的吸收直径,加强矿质养分的空间有效性; 通过释放有机酸、 土壤酶,活化土壤中被固定的矿质养分; 通过根外菌丝上较低 Km 值的矿质养分转运蛋白,保证养分从土壤至根外菌丝的转运效率; 通过矿质养分在菌丝内运输形式的改变,增强养分的运输速率; 通过诱导共生植物矿质养分转运蛋白表达,提高植、 菌间养分的转运效率。相较于 AM 真菌促进共生植物养分吸收,植物反馈真菌碳水化合物的研究相对较少。鉴于 AM 真菌与植物共生关系在生态系统中的重要作用,明晰植、 菌间矿质养分和碳水化合物交换的具体场所(丛枝、 根内菌丝、 根外菌丝)、 具体形式(离子、 聚合物、 氨基酸、 蔗糖、 单糖)、 具体过程(主动运输)具有重要科学意义。本文对 AM 真菌与共生植物物质交换的丛枝、 菌丝双膜结构,氮(N)、 磷(P)、 糖等物质交换的具体形式以及跨双膜、 耗能量、 互耦连的物质交换过程进行综述,并从物质交换的场所、 形式、 过程三个方面提出了植、 菌物质交换的研究方向。     

根际养分活化与吸收过程的定量模拟研究进展

在论述植物根系作为养分的主动吸收槽，对根示养分生物有铲性产生重要作用的前提下，本文扼要讨论了根际ＰＨ值变化，根分泌螯合物与 性物及根际微生物在根际土壤养分活化中的作用过程，并重点评述了有关养分活化与吸收模拟模型的进展与发展趋势。     

腐植酸促进植物生长的机理研究进展

【目的】腐植酸在我国农业生产中发挥了重要作用,许多研究证实,腐植酸具有促进植物生长的功能,本文从腐植酸刺激植物根系生长、调控土壤与肥料养分转化及肥料利用率和影响土壤微生物和酶活性方面,系统总结了国内外施用腐植酸促进植物生长的途径,阐述了腐植酸对植物生长促进作用的机理,旨在梳理腐植酸促进植物生长机理的研究现状,为腐植酸的进一步研究和应用提供参考依据。[主要进展]1）腐植酸能够对植物产生类似生物刺激素的效应。它能够提高植物根系H+-ATP酶等的活性、刺激植物根伸长和侧根生长点的增加,从而增加根系活力及植物根系与土壤养分的接触面积,增加植物对养分的吸收;2）逆境胁迫下,腐植酸能够通过调节植物体内的新陈代谢并改善植物生长环境,缓解甚至消除逆境胁迫对植物的伤害,从而促进植物生长;3）腐植酸能够通过与氮素、磷素和钾素发生结合效应,与磷酸盐产生竞争效应和对钾离子的吸附作用固持与活化土壤与肥料中的养分,提高土壤肥料有效性和缓释性能,提高肥料利用率,从而促进植物生长;4）腐植酸还能够影响土壤中与养分转化相关的酶活性和微生物群落结构及数量,在活化养分的同时,保蓄养分,降低养分的损失,为植物生长保障持久的养分供应;5）腐植酸对植物生长的促进效应受腐植酸结构特征、添加量和供试植物种类等因素的影响。[建议与展望]由于技术手段的限制和研究技术的差异,人们对腐植酸促进植物生长机理的认识还不够系统和深入,因此,腐植酸的基本特征、影响腐植酸作用的主控因子、土壤-植物系统中腐植酸促进植物生长的主要途径和腐植酸对土壤功能性微生物等的影响都将成为未来研究的重要方向。     

Growth of bedding plants and poinsettias in mineral wool and mineral wool/peat substrates

Abstract

Studies were conducted to ascertain the suitability of mineral wool (MW), either alone or in combination with sphagnum peat moss, as a substrate for potted greenhouse plants. Two types of hydrophyllic mineral wools, cleaned mineral wool (CMW) and uncleaned mineral wool (UMW), were used. Unamended CMW had a low bulk density, excellent water holding capacity, good aeration, but a high pH. Once peat moss was added to the CMW, bulk density remained low, water holding capacity remained good, and the pH dropped to a more suitable level. Unamended UMW had a high bulk density, good water holding capacity, poor aeration, and a high pH. Once peat moss was added to UMW, bulk density decreased, water holding capacity remained good, aeration increased, and the pH decreased to a more optimal level. CMW and UMW, were used unamended, as well as amended with 25%, 50%, and 75% peat moss. Two bedding plants, Impatiens walleriana ’Dazzler Violet’ and Begonia semperflorens ’Whiskey’ were grown for six and nine weeks respectively, and Euphorbia pulcherrima ’Glory’ was grown for 20 weeks, in nine different substrates. Plants grown in unamended CMW and UMW were generally smaller in size and lower in fresh weight than plants grown in 50% MW/50% peat moss. The plants grown in MW with either 25% or 75% peat moss were similar in size and weight to plants grown in 50% MW/50% peat moss. Plant tissue analysis showed that generally plants were receiving adequate nutrition.     

The effect of mineral fractions on physical and phosphorus-related chemical properties of peat-based substrates for pot plants

Physicochemical traits of peat-based pot substrates prepared from mixing of 20 or 40?vol.% of some different mineral fractions (sub. 1 to 7, subjected to decreasing amount of clay content of 66.1, 61.2, 49.7, 38.5, 26.0, 23.7 and 19.4%, respectively) with black peat were evaluated and then phosphorus uptake of poinsettia (Euphorbia pulcherima) simulated mechanistically as a case study pot plant. For preparation of substrate number 8, pure peat was mixed with 40?vol.% of the same mineral component as substrate number 6 (with 23.7% clay). Result revealed that adding different mineral fractions up to 40?vol.% to pure peat, water-holding capacity and total pore volume were reduced only by 11 and 15?vol.%, respectively. It was found that keeping the moisture content of peat-based substrates with 20?vol.% of mineral soils around 60%–70%, the optimum ventilation and enough free space of about 15%–25% will be provided around the root system. In addition, simulated P uptake did not change significantly with addition of 20?vol.% of different mineral components in peat-based substrates. As a result, P uptake mainly was dependent on the amount of plant available P level than different mineral fractions.     

Influence of mineral nutrition on denitrification on plants in nutrient solution culture

In solution culture experiments with spring wheat the effect of nitrogen sources, single nutrient deficiency and oxygen supply of the nutrient solution on denitrification was studied by means of the acetylene inhibition method. No denitrification was observed with ammonium nutrition, while denitrification was almost equally high with nitrate and a mixture of nitrate and ammonium nutrition. Discontinuing potassium for 7 and 14 days increased denitrification. Discontinuation of P for 14 days also increased total denitrification, whereas no difference from the complete nutrient solution was observed in Fe deficiency. Denitrification remained at a very low level, when Mg supply was discontinued. Denitrification potential of excised roots was high in K deficiency. It was also high at the beginning of Fe deficiency, whereas P and Mg deficiency had no effect on denitrification potential as compared to roots in complete nutrient solution. The differences in total denitrification are due to the effects of individual nutrient deficiency on root growth, root respiration and denitrification potential.     

Effect of light and water stress on mineral element composition of plants 1

Many factors affect the composition of mineral elements in plants. The effects of many of these factors, such as element concentration, temperature, pH, plant part, plant age, metabolic inhibitors, element interactions, fertilizer, and type of soil, have been studied extensively by many scientists who are concerned with plant mineral nutrition. However, relatively few studies have focused on the effects of light and water stress. The objective of this review was to consider some of the effects that light and water stress have on the mineral element composition of plants.     

Root-induced changes in the rhizosphere: Importance for the mineral nutrition of plants

Root-induced changes in the rhizosphere may affect mineral nutrition of plants in various ways. Examples for this are changes in rhizosphere pH in response to the source of nitrogen (NH₄-N versus NO₃-N), and iron and phosphorus deficiency. These pH changes can readily be demonstrated by infiltration of the soil with agar containing a pH indicator. The rhizosphere pH may be as much as 2 units higher or lower than the pH of the bulk soil. Also along the roots distinct differences in rhizosphere pH exist. In response to iron deficiency most plant species in their apical root zones increase the rate of H⁺ net excretion (acidification), the reducing capacity, the rate of Fe^III reduction and iron uptake. Also manganese reduction and uptake is increased several-fold, leading to high manganese concentrations in iron deficient plants. Low-molecular-weight root exudates may enhance mobilization of mineral nutrients in the rhizosphere. In response to iron deficiency, roots of grass species release non-proteinogenic amino acids (?phytosiderophores”?) which dissolve inorganic iron compounds by chelation of Fe^III and also mediate the plasma membrane transport of this chelated iron into the roots. A particular mechanism of mobilization of phosphorus in the rhizosphere exists in white lupin (Lupinus albus L.). In this species, phosphorus deficiency induces the formation of so-called proteoid roots. In these root zones sparingly soluble iron and aluminium phosphates are mobilized by the exudation of chelating substances (probably citrate), net excretion of H⁺ and increase in the reducing capacity. In mixed culture with white lupin, phosphorus uptake per unit root length of wheat (Triticum aestivum L.) plants from a soil low in available P is increased, indicating that wheat can take up phosphorus mobilized in the proteoid root zones of lupin. At the rhizoplane and in the root (root homogenates) of several plant species grown in different soils, of the total number of bacteria less than 1 % are N₂-fixing (diazotrophe) bacteria, mainly Enterobacter and Klebsiella. The proportion of the diazotroph bacteria is higher in the rhizosphere soil. This discrimination of diazotroph bacteria in the rhizosphere is increased with foliar application of combined nitrogen. Inoculation with the diazotroph bacteria Azospirillum increases root length and enhances formation of lateral roots and root hairs similarly as does application of auxin (IAA). Thus rhizosphere bacteria such as Azospirillum may affect mineral nutrition and plant growth indirectly rather than by supply of nitrogen.     

Drought and salinity: A comparison of their effects on mineral nutrition of plants

The increasing frequency of dry periods in many regions of the world and the problems associated with salinity in irrigated areas frequently result in the consecutive occurrence of drought and salinity on cultivated land. Currently, 50% of all irrigation schemes are affected by salinity. Nutrient disturbances under both drought and salinity reduce plant growth by affecting the availability, transport, and partitioning of nutrients. However, drought and salinity can differentially affect the mineral nutrition of plants. Salinity may cause nutrient deficiencies or imbalances, due to the competition of Na⁺ and Cl^– with nutrients such as K⁺, Ca²⁺, and NO . Drought, on the other hand, can affect nutrient uptake and impair acropetal translocation of some nutrients. Despite contradictory reports on the effects of nutrient supply on plant growth under saline or drought conditions, it is generally accepted that an increased nutrient supply will not improve plant growth when the nutrient is already present in sufficient amounts in the soil and when the drought or salt stress is severe. A better understanding of the role of mineral nutrients in plant resistance to drought and salinity will contribute to an improved fertilizer management in arid and semi‐arid areas and in regions suffering from temporary drought. This paper reviews the current state of knowledge on plant nutrition under drought and salinity conditions. Specific topics include: (1) the effects of drought and salt stress on nutrient availability, uptake, transport, and accumulation in plants, (2) the interactions between nutrient supply and drought‐ or salt‐stress response, and (3) means to increase nutrient availability under drought and salinity by breeding and molecular approaches.     

Effect of mineral nutrition on contents of organic constituents in sweet potato plants during growth

Although chinese yam plants are an important crop in Japan, relatively little is known about their content of the organic constituents. IZAWA and NATAKE (1,2,3) showed some aspects of the effect of the fertilizer treatment on the organic composition of chinese yam plants at various phase of their vegetation. Many reports on chinese yam plants have appeared; nevertheless, the nature of carbohydrate and nitrogen metabolism has remained unknown. However, there are a number of excellent reports (4, 5, 6) which directly or indirectly have a bearing on these biochemical phase in sweet Potato plants. Therefore, the objectives of the Present study were twofold : a) to determine the contents of sugars, starch, alcohol-insoluble solids, and various nitrogen constituents in sweet potato plants during growth as affected by mineral nutrition, and b) to compare the effect of mineral nutrition on sweet potato plants with its effect on chinese yam plants.     

木芙蓉营养生长旺期主要矿质元素的吸收与分布特征

木芙蓉是一种观赏和药用价值较高的多年生木本花卉。在大田条件下,研究营养生长旺期木芙蓉主要矿质元素的含量与分布特征,可为其科学施肥提供技术支撑。以营养生长旺期的两个木芙蓉品种(早花品种"牡丹红"和晚花品种"醉芙蓉")为研究对象,称量根、茎、叶等器官的生物量,测定其中氮、磷、钾、钙、镁、铁、锰、锌元素含量。结果表明:(1)在营养生长旺期,"牡丹红"和"醉芙蓉"整株生物量无差异,但前者茎的比重大于后者,后者根的比重大于前者。(2)磷在木芙蓉不同器官含量无差异,叶片中其他矿质元素含量显著高于茎和根;对于相同器官,早花品种叶片中钙的含量低于晚花品种,其余元素含量无差异。(3)木芙蓉不同器官的养分吸收累积量与含量类似,除磷、钾、镁、铁以外,其余元素在叶中积累量高于根和茎;早花品种整株氮、钙和铁的积累量低于晚花品种。(4)早花品种氮、磷、钾、钙、镁、铁、锰、锌养分累积量分别为4.34、0.87、4.99、3.12、1.44、0.15 g·株^-1和8.50、5.86 mg·株^-1,晚花品种累积量分别为5.92、1.11、5.71、4.35、1.74、0.22g·株^-1和12.52、7.52 mg·株^-1。因此,木芙蓉生长阶段不仅需要施用氮、磷、钾大量元素,还要注意中微量元素的补充。种植年限相同的晚花品种施肥量稍高于早花品种,但不同养分施用比例的规律类似,营养生长旺期两者氮、磷、钾、钙、镁、铁、锰、锌养分吸收比例平均为1∶0.20∶1.06∶0.73∶0.31∶0.04∶(2.04×10–3)∶(1.31×10–3)。然而,木芙蓉整个生育期肥料施用数量和时期有待进一步研究。     

不同生育期遮荫条件下番茄矿质氮的分配效应

光合有效辐射是影响作物生长发育、产量构成以及营养状况的重要因子。由于遮荫造成的光照强度的降低经常引起干物质积累的减少和营养状况的下降。然而，在夏季晴天中午遮荫并不总是导致营养状况的降低。该文以番茄为材料，观测了不同生长阶段(开花早期，盛花期和开花后期)夏季午间遮荫(0遮荫，40%遮荫和75%遮荫)对矿质氮在番茄各器官中的含量及其分配的影响，发现不同时期影响不同。遮荫不影响开花早期和盛花期叶片氮的含量及其分配。但开花后期，40%遮荫使叶氮含量增加，叶、茎、茬中氮的分配指数高于开花早期和盛花期，并且产量增加。这些结果表明，在某些时期中度遮荫可以克服夏天辐射过强、气温过高对番茄的不良影响，有利于改善番茄氮素营养状况和提高经济产量，在生产中有一定意义。