调控技术对棉花干物质积累、养分吸收的影响

以新陆早13号为材料,研究了调控技术对新疆棉花干物质积累和养分吸收的影响,结果表明:在水肥及化控总量不变的前提下运用调控技术增加了各生育期棉株地上部分干物质积累量、养分吸收量和分配率,在营养生长时期提高了干物质和养分在营养器官中的分配,在生殖生长时期提高了干物质和养分在生殖器官中的分配;调控技术还进一步提高了棉株干物质积累与养分吸收的相关性.     

旱地土壤氮素、有机质状况及与作物吸氮量的关系

在具有典型半干旱气候特征的陕西永寿选取6种不同肥力水平的田块,分层采集0～100cm土样,测定各土层可矿化氮、全氮及有机质含量,研究其与作物吸氮量之间的关系,结果表明,各土层可矿化氮、全氮及有机质之间存在着良好的相关性,可矿化氮与作物吸氮量之间的相关程度高于与全氮、有机质间的相关性,可矿化氮加上土壤起始矿质氮后,相关系数更高,0～45cm土层的可矿化氮、全氮、有机质与作物吸氮量的相关性高于45cm以下的土层,且以30～45cm土层的为最好;以土壤全氮或有机质作为评价土壤供氮能力的指标,效果不如可矿化氮。     

大豆黄酮对奶牛血清钙、磷及葡萄糖水平的影响

为研究大豆黄酮对奶牛血清钙、磷和葡萄糖水平的影响,40头胎次、产奶量、泌乳期相近的中国荷斯坦奶牛随机分成4组(n=10),试验组奶牛日粮中分别添加45mg/kg、60mg/kg和75mg/kg的大豆黄酮,在试验前及试验开始后第10d、20d和30d采颈静脉血,测定四组奶牛血清钙、磷和葡萄糖水平。结果表明:与对照组相比较,Dal组中血清钙、磷和葡萄糖变化均不显著;Da2组血清钙在第30d时显著高于对照组(P<0.05);Da3组第10d和20d时血清钙水平显著高于对照组(P<0.05),第30d时血清钙水平极显著高于对照组(P<0.01),而血糖水平显著高于对照组(P<0.05)。     

植物高亲和性钾离子转运系统

钾是植物生存的必需元素,而K＋必须从细胞外摄取以满足植物自身的生理需要。植物K＋吸收可分为高亲和吸收与低亲和吸收,其中植物高亲和性K＋转运体包括HAKs和HKTs。在普遍缺钾的陆生环境中,HAKs和HKTs在转运K＋时发挥了主要作用。主要综述了这2个转运体的功能、转运机制和最新研究进展。     

Endogenous 5-HT outflow from chicken aorta by 5-HT uptake inhibitors and amphetamine derivatives

Chemoreceptor cells aggregating in clusters in the chicken thoracic aorta contain 5-hydroxytryptamine (5-HT) and have voltage-dependent ion channels and nicotinic acetylcholine receptors, which are characteristics typically associated with neurons. The aim of the present study was to investigate the effects of 5-HT uptake inhibitors, fluvoxamine, fluoxetine and clomipramine (CLM), and amphetamine derivatives, p-chloroamphetamine (PCA) and methamphetamine (MET), on endogenous 5-HT outflow from the isolated chick thoracic aorta in vitro. 5-HT was measured by using a HPLC system with electrochemical detection. The amphetamine derivatives and 5-HT uptake inhibitors caused concentration-dependent increases in endogenous 5-HT outflow. PCA was about ten times more effective in eliciting 5-HT outflow than MET. The 5-HT uptake inhibitors examined had similar potency for 5-HT outflow. PCA and CLM increased 5-HT outflow in a temperature-dependent manner. The outflow of 5-HT induced by PCA or 5-HT uptake inhibitors was independent of extracellular Ca²⁺ concentration. The 5-HT outflow induced by CLM, but not that by PCA, was dependent on the extracellular NaCl concentration. These results suggest that the 5-HT uptake system of 5-HT-containing chemoreceptor cells in the chicken thoracic aorta has characteristics similar to those of 5-HT-containing neurons in the mammalian central nervous system (CNS).     

Effects of Root Water Uptake Efficiency on Soil Water Utilization in Wheat (Triticum aestivum L.) under Severe Drought Environments

Improving wheat production in drought‐prone areas is the key to meet the increasing global demand. The importance of root traits, especially, the structural traits such as root volume and rooting depth, has been well recognized to confer drought tolerance in wheat. However, generation of knowledge on root water uptake efficiency and its application in drought adaptation breeding had lagged behind. The main objective of this study was to evaluate the relevance of the root water uptake efficiency to biomass production under acute soil water deficit in six wheat genotypes. Pot experiments were conducted under polythene rainout shelters at Hokkaido University, Sapporo, Japan, in 2010 and 2011. Under drought that was measured as smaller critical fraction of transpirable soil water (FTSW), the root systems with less reduction water uptake efficiency were found to postpone the relative transpiration decline. This study also showed the existence of substantial genotypic variation on the root water uptake efficiency among the wheat genotypes. The expression of hydrophobic root morphology under drought environments, however, did not explain the results obtained on the relative root water uptake efficiency, indicating other regulative mechanisms in operation for the regulation of transverse water flow in the roots. These findings provide new understanding of drought adaptation in wheat through variations in the root water uptake efficiency.     

Soil–root cross‐talking: The role of humic substances

The biological activity of humic substances (HS) has been elucidated in the last 40 years. Growth enhancement from HS has been demonstrated in several plants in the laboratory and the field. Morphogenesis effects have also been investigated and include induction of lateral root formation and root hair initiation in intact plants and stimulation of root and shoot development in treated cell calluses. HS enhance nutrient use efficiency, aiding assimilation of both macro and microelements and promoting plant growth by the induction of carbon, nitrogen, and secondary metabolism. The review aims are to: (1) shed light on the mechanism by which plants “talk” with soil through humic substances, (2) elucidate the plant responses to the stimulatory effects of HS, the regulatory circuits that allow plants to cope with humus, and the feedback between plant community structures, and (3) show (in light of recent debate about the alkaline extraction of soil humic substances) the plant capability to acquire biologically active substances from soil. It will be shown that plants modify soils, creating and maintaining favorable habitats for growth and survival. Therefore, organic substances exuded by roots are not a wasteful loss of carbon and energy. They represent an evolved strategy by which plants “talk” to the soil. The mobilization of bioactive organic/humic substances from bulk soil or bulk humus is critical to plant and soil health.     

普洱茶中没食子酸及其改善饮食诱导的糖脂代谢紊乱研究进展

糖脂代谢紊乱是引发心血管疾病、糖尿病和脂肪肝的重要原因之一。普洱茶中的没食子酸能够通过调节能量代谢和脂肪细胞分化、促进葡萄糖吸收与利用、提高胰岛素敏感性,进而改善饮食诱导引起的葡萄糖和脂质代谢紊乱。没食子酸通过AMPK途径、IR-Akt途径以及PPAR-γ受体调节线粒体能量代谢、胰岛素敏感性和葡萄糖吸收,从而维持糖脂代谢稳态。本文综述了普洱茶中的没食子酸及其改善饮食诱导的糖脂代谢紊乱作用和作用机制的研究进展。     

马尾松不同种源P素吸收动力学特征

通过水培试验研究田间试验下对P肥反应存在显著差异的5个马尾松种源在3种P水平(水培试验中为0、5、20μmol·L-1)下根系P素吸收总量、离子动力学参数(Imax、Km和Cmin)等特征。研究表明,随着溶液P素浓度的升高,马尾松各参试种源的苗高生长、P素吸收总量均有不同程度的增加,但其变化因种源而异。福建武平和广东信宜两种源对P素增加的反应敏感性(高生长和P素吸收增长率)远低于其他3个参试种源,与大田P肥试验结果一致。对1年生和半年生水培幼苗离子动力学参数测定结果揭示,随着培养溶液P素浓度的升高,各参试种源的Imax下降,Km和Cmin增加。比较分析发现,低P水平下广东信宜和福建武平两种源具有相对较小的Km和Cmin,相对较大的Imax,对分布于武夷山脉南端的福建武平种源尤其如此。     

限量灌水和施磷对冬小麦养分吸收及利用的影响

通过大田试验研究了冬小麦在整个生育期阶段植株的养分吸收量和肥料利用效率的变化规律。本研究以西农‘979’小麦为试验材料,试验采取3个灌水水平即W₁,W₂及W₃,分别为2 400 m³·hm^-2、1 800 m³·hm^-2和1 200 m³·hm^-2。施磷设4个水平即F₁、F₂、F₃及F₄,施磷肥(纯P₂O₅)量分别是0、60、120及180 kg·hm^-2。结果表明：在施氮肥相同的情况 下,灌水和增施磷肥均能够促进植株对氮、磷的吸收量。随着施磷量的增加,灌溉水利用效率及产量也随着显著增加。在F₄处理条件下,W₂处理的子粒产量高于W₁、W₃处理,在W₂处理基础上再增加灌水量,子粒产量无显著提高,且显著降低了水分利用效率。这说明灌水和施磷显著提高子粒的产量,但过量灌水会导致子粒产量下降,适量灌水、增施磷肥可以显著提高子粒产量。在本试验条件下,灌水量在1 800 m³·hm^-2和施磷肥(纯P₂O₅)量在120 kg·hm^-2时,促进小麦的生长发育进程,施磷对土壤水分不足的补偿效应主要是增加单位面积穗数,施肥增加了穗粒数,从而增加了产量,提高水分和磷素利用效率。