水稻根表铁膜对磷的富集作用及其与水稻磷吸收的关系

采用溶液培养方法,使铁毒耐性不同的两个基因型水稻根表分别形成有铁膜和无铁膜的根系,研究水稻根表铁膜对磷的富集作用及其与水稻磷吸收的关系。不同基因型水稻根表形成的铁膜厚度存在显著差异,对介质中磷的富集能力也有显著差异。根表形成的铁膜越厚,对介质中磷的富集作用也越大,即根表铁膜数量与铁膜对磷的富集量呈显著正相关。铁膜对磷的富集作用是一个化学过程,吸附可在0.5~1.0 h内达到饱和。根表铁膜明显促进水稻对磷的吸收,表明在淹水降低土壤磷有效性时,水稻根表铁膜富集的磷可作为磷库,保证水稻能正常吸收利用磷。     

稳定同位素技术鉴别库尔勒香梨产地可行性研究

为开展碳、氮、氢、氧(C、H、O、N)稳定同位素鉴别库尔勒香梨产地的可行性研究,明确新疆库尔勒香梨δ¹³C、δ¹⁵N、δ²H、δ¹⁸O值,本研究以甘肃香梨和陕西红香酥梨作为对照,采用稳定同位素比值质谱仪(IRMS)分析新疆库尔勒香梨与对照样品的δ¹³C、δ¹⁵N、δ²H、δ¹⁸O值,并采用正交校正的偏最小二乘判别分析(OPLS-DA) 鉴别新疆库尔勒香梨产地真实性。结果表明,新疆、甘肃两个产区香梨与陕西产区红香酥梨的δ¹³C、δ¹⁵N、δ²H、δ¹⁸O值存在显著差异(P<0.05)。新疆产区的66份库尔勒香梨判别准确率为95.45%;甘肃产区的20份香梨样品判别准确率为60%;陕西产区的23份红香酥梨样品判别准确率为95.65%。C、N、H、O 4种稳定同位素可有效鉴别新疆库尔勒香梨和陕西红香酥梨,但在新疆库尔勒香梨与甘肃香梨鉴别方面,误判率较高,如果能结合其他鉴别技术,则有可能出现较好的鉴别效果。本研究为库尔勒香梨产地真实性鉴别提供了科学依据。     

用SahysMod模型研究不同灌排管理情景土壤水盐动态

银北灌区是宁夏土地整治和高标准灌溉绿洲农田建设的重点区域。该区域耕荒地交错分布、土壤盐渍化严重。通过模型分区模拟,在土地整治过程中建立完整、配套的灌排系统是解决区域土壤盐渍化的有效措施。该研究以银北灌区典型区域-西大滩为例,综合考虑荒地与耕地土壤属性的空间变异性,以2015—2016年土壤盐分数据进行率定,2017年盐分数据作为验证,利用SahysMod探索在土地整治过程中不同灌排管理下未来10 a内土壤水盐动态变化。结果表明,现有灌排管理下(即灌水量为670 mm,灌溉水电导率为1.05 dS/m,排水沟深1.5 m),荒地土壤盐分在预测初期(2017—2022年)逐年升高,预测后期(2023—2027年)变化平缓;耕地土壤盐分在预测初期变化缓慢,预测后期逐年增加。加大灌水量是解决土壤盐渍化的一个重要途径,可以有效延迟耕地盐分累积到障碍水平的时间;在灌溉水电导率为0.6 dS/m情况下,未来10 a内耕地都不会受到盐害胁迫;现有灌排管理下,在2024年以后作物生长就会受到盐害胁迫,当灌溉水电导率继续增加时,作物生长受到胁迫的时间相应提前。通过土地整治,加深排水沟深度可以延迟土壤盐分达到障碍水平的时间。在整治过程中深为2.2 m的排水沟,可保证未来10 a内耕地盐分小于1.7 dS/m,区域内玉米可正常生长。研究可为在土地整治过程中的灌排管理及土壤盐渍化防治提供建议。     

基于格网的石漠化地区生态系统服务与经济空间耦合

[目的]分析石漠化地区生态系统服务价值与经济的空间耦合关系,为石漠化地区生态环境保护与社会经济协调发展提供依据。[方法]以贵州省盘州市为例,基于格网尺度,计算了研究区生态服务价值(ESV)与国内生产总值GDP,并利用耦合协调模型,对两者间的耦合协调发展程度进行定量评估。[结果]①盘州市ESV热点区主要分布在东北部的几个少数民族乡镇,冷点区主要分布在经济发展较快且城市化率较高的区域;②盘州市GDP在空间上呈现出局部高的特点,高值区主要集中在石桥镇、亦资街道、翰林街道等工业镇和政治、经济、文化中心;③盘州市ESV与GDP耦合协调度值较低,空间上存在明显的自相关性,耦合协调度较低的区域主要分布在盘州市东南部、北部以及中部;④盘州市ESV与GDP耦合协调度类型以严重失调衰退经济损益型为主,占区域总面积的79.95%。[结论]盘州市ESV与GDP在空间上存在一定矛盾,耦合协调度较低,兼顾生态环境保护与经济发展有助于提升协调度。     

我国脲醛树脂制备技术研究概述

介绍了我国近年来脲醛树脂制备技术和实际应用概况,总结了生产实践中较为实用的树脂制备和改性方法,探讨了脲醛树脂目前存在问题,并指出发展方向。     

上海半自然森林更新苗物种组成与多样性研究

城市半自然森林具有独特的群落结构和生物多样性特征,研究城市化影响的半自然森林更新特征,可以为城市生物多样性保育与地带性植被恢复重建提供借鉴。文章以上海辰山残存半自然森林1 hm^2固定监测样地为对象,调查分析半自然森林更新苗的物种组成特征。结果表明:1 hm^2样地更新苗共5 937株,分属22科32属37种,其中上海自然分布的乡土种占57.89%,明显高于城市人工林的乡土树种比例;香樟、构树、天竺桂、朴树和小蜡等5种更新苗占总数的57.2%,聚集性分布格局明显;在11个植被群落类型中,各类型更新苗的丰富度普遍较高,不同树种的更新苗存活和发育潜力存在差异。     

AsKC11, a Kunitz Peptide from Anemonia sulcata,Is a Novel Activator of G Protein-Coupled Inward-Rectifier Potassium Channels

(1) Background: G protein-coupled inward-rectifier potassium (GIRK) channels, especially neuronal GIRK1/2 channels, have been the focus of intense research interest for developing drugs against brain diseases. In this context, venom peptides that selectively activate GIRK channels can be seen as a new source for drug development. Here, we report on the identification and electrophysiological characterization of a novel activator of GIRK1/2 channels, AsKC11, found in the venom of the sea anemone Anemonia sulcata. (2) Methods: AsKC11 was purified from the sea anemone venom by reverse-phase chromatography and the sequence was identified by mass spectrometry. Using the two-electrode voltage-clamp technique, the activity of AsKC11 on GIRK1/2 channels was studied and its selectivity for other potassium channels was investigated. (3) Results: AsKC11, a Kunitz peptide found in the venom of A. sulcata, is the first peptide shown to directly activate neuronal GIRK1/2 channels independent from Gi/o protein activity, without affecting the inward-rectifier potassium channel (IRK1) and with only a minor effect on K_V1.6 channels. Thus, AsKC11 is a novel activator of GIRK channels resulting in larger K⁺ currents because of an increased chord conductance. (4) Conclusions: These discoveries provide new insights into a novel class of GIRK activators.     

Genetic Diversity and Population Structure in the Heavily Exploited Korean Rockfish,Sebastes schlegeli,in Korea

The Korean rockfish, Sebastes schlegeli, is a valuable and intensively exploited species in Korea. We discuss the genetic diversity and genetic structure of four Korean rockfish populations using eight microsatellite loci. In total, 161 different alleles from 138 individuals were observed. Average allele number per locus ranged from 2.5 to 23 and allelic richness varied from 13.38 to 14.63 within a population. Despite a long history of stocking practices, we found very high levels of polymorphism (mean heterozygosity = 0.810), which is comparable to other congeneric species. No significant difference in genetic diversity and molecular genetic variance (F_ST and R_ST) was observed among four local samples (P > 0.1). Little indication of contemporary inbreeding (F_IS= 0.051) or population structure (K = 1) was detected. This absence of differentiation may reflect high levels of gene flow along the coast of Korea. Our study demonstrates that rockfish in Korea should be managed as a single unit. Currently, the species does not appear to be genetically threatened, but the potential for a rapid loss of genetic diversity remains. This information on the genetic characteristics of Korean rockfish populations has important implications for fisheries management and conservation efforts, and will aid in the sustainable exploitation of the fishing resources and the preservation of biodiversity.     

钙源及水平对肉仔鸡体内电解质平衡及血脂水平的影响

本文旨在研究采用不同钙源及水平的日粮对肉仔鸡体内电解质平衡及血脂水平的影响.试验采用二因素有重复完全交叉区组设计,选用144只健康AA肉仔鸡,随机分成4处理,每个处理6个重复,每个重复6只.饲粮采用2种钙源(碳酸钙、氯化钙)、2个钙水平(0.90%、1.15%),试验期28 d.结果表明:①与碳酸钙相比,日粮中氯化钙可降低血清Na++K+-Cl-水平(P<0.05)、提高Cl-水平(P<0.05),降低腹脂率(P<0.05)和血脂水平.②高水平钙可提高血清Ca2+水平(P<0.05).降低腹脂率和血脂水平(P<0.05).③钙源和水平互作对各指标均无显著影响(P>0.05).总之,日粮选用1.15%氯化钙虽对电解质平衡产生了一些影响,但可以较好地降低腹脂率和血脂水平.     

Comparison and analysis of the staining methods for cholesterol

Cholesterol staining is a useful approach for the visualization, localization and quantification of cholesterol in cells or tissues, which is frequently used to investigate the mechanisms of some diseases such as arteriosclerosis, Niemann-Pick disease type C, and Alzheimer's disease. It can be accomplished through various microscopes including light microscope, fluorescent microscope, and electronic microscope. During the past decades, various types of methods for cholesterol staining with different principles have been established for different applications. It is important to choose an appropriate method that is suitable for particular experimental aims, features and conditions. At present, three kinds of methods are frequently applied: filipin fluorescent method, BCθ(a biotinylated and carlsberg protease-nicked derivative of perfringolysin O) toxin method, and cholesterol oxidase-diaminobenzidine(oxidase-DAB) method. Four kinds of methods are scarcely applied: Schultze method, perchloric acid-naphthoquinone method(PAN), digitonin method, and o-phthalaldehyde method. In this review, the principles, advantages, and disadvantages of these methods are compared with the emphasis of the application, sensitivity, and specificity.