光敏色素研究进展

综述了自20世纪20年代光敏色素被发现以来的研究概况及进展.主要包括(1)光敏色素作为主要光受体在调节从种子萌发到器官衰老的植物生长过程中所发挥的作用;(2)光敏色素的5种不同基因型及基因同源性和主要的反应方式,尤其是光敏色素的主要分子基因PhyA和PhyB在反应方式上的区别;(3)从生物化学和分子水平阐述了光敏色素的生理功能,其中包括光敏色素对细胞生长的调节,光敏色素是如何通过调节光周期反应进而调节了生长和开花的,光敏色素对基因表达的调控以及光敏色素与植物激素协同作用于植物生长和育性等;(4)虽然迄今为止人们极少研究光敏色素和植物激素在苜蓿秋眠中的作用,但对此方面提出了研究展望.     

四川省优质蛋白玉米农艺性状的遗传变化和相关性研究

应用NC-Ⅱ交配设计,研究分析了四川省1991和2001年优质蛋白玉米9个农艺性状的遗传参数。结果表明:自交系总体在大多数性状上仍保持丰富的遗传变异,有继续改良利用的潜力。一般配合力方差占遗传方差的比重大于55%的性状包括产量、穗行数、百粒重、穗粒重和株高;行粒数、每株穗数和抽丝期性状一般配合力方差占遗传方差的比重在30.03%~47.26%之间。值得注意的是,产量性状的加性方差有降低的趋势,遗传基础可能变窄。本文还对农艺性状的相关性进行了分析,并结合国内外的研究和育种实践,讨论了优质蛋白玉米育种的问题。     

不同水氮耦合管理下耕层土壤的氮动态

以中国科学院封丘农业生态试验站水氮耦合长期试验地为研究平台,采集了不同水氮耦合管理下耕层0～10 cm、10 ～ 20 cm和0～20 cm土壤,测定了六种形态的氮(无机氮、有机氮、酸解有机氮、酸解铵态氮、溶解性有机氮和微生物生物量氮)和三种与氮周转密切相关的生物性指标(脲酶活性、蛋白酶活性和硝化势).三因素方差分析结果表明,施氮和耕层深度对六种形态氮均有显著作用,而灌水对这六种形态氮无显著作用.单因素方差分析结果显示施氮明显提高了耕层0 ～ 20 cm土壤无机氮、有机氮、脲酶活性及硝化势,而对土壤酸解有机氮和酸解铵态氮无显著影响;六种形态的氮、蛋白酶活性及硝化势均不受灌水量的影响.不同水氮耦合管理下耕层0 ～ 10 cm土壤六种形态氮、脲酶活性、蛋白酶活性及硝化势几乎均明显地高于10～20 cm土壤.通过对不同水氮耦合管理下耕层土壤氮动态的研究,本研究得出最佳的水氮耦合管理模式是灌水至20 cm土层的田间持水量和每季施氮190 kg hm-2.     

Genetic variation in cassava for postharvest physiological deterioration

Cassava storage roots start deteriorating 1 to 3 days after harvest due to postharvest physiological deterioration (PPD) which reduces the potential of cassava as a commercial crop. The objective of this study was to examine the extent of genetic variability in cassava for PPD. Genetic variability is important in selecting suitable genotypes for crop improvement. Twelve cassava genotypes were evaluated in a randomized complete block design at three different locations in Uganda for five different harvest times, and PPD assessment was done 7 days after each harvest time. Genotype, location, harvest time, genotype × harvest time and harvest time × location were highly significantly different for PPD. Estimates of phenotypic, genotypic and environmental variance components revealed that a large portion of the phenotypic variance was accounted for by the genotypic component which is an indication of substantial genetic variability among the test genotypes for PPD. This genetic variability is important in a breeding programme because it indicates that significant genetic gain through phenotypic selection is possible for PPD. The results give guidance to breeding efforts for improved shelf life of cassava storage roots.     

雌马酚的产生、生物学功能及潜在应用

雌马酚(equol)是大豆异黄酮在动物肠道微生物菌群作用下的代谢产物之一,具有比大豆异黄酮更高的生物学活性。除了激素样作用外,雌马酚还具有抗氧化、免疫调控及保健功能,在畜禽上的研究表明其具有改善肉品质、缓解氧化应激的作用。本文主要从雌马酚的理化性质、产生与代谢、影响生成的因素、生物学功能及应用等方面来综述,旨在为雌马酚在畜禽上的科学应用提供思路。     

植物提取物对猪的生物学功能及其相关机制

抗生素在养猪生产中的大量使用可导致细菌耐药性的产生、肉及肉制品药物残留等问题,危害动物和人的健康。植物提取物是以植物为原料,经过一系列物理、化学提取过程,得到的由一种或多种天然活性成分构成的植物产品。近年来,植物提取物作为抗生素替代产品的研发成为营养研究的热点之一。本文结合国内外关于植物提取物在养猪生产中的应用研究,综述了植物提取物在抑制有害微生物、免疫调控、抗氧化和代谢调控等方面的作用及其相关机制。     

11年生杉木全同胞子代林遗传效应研究

通过对１９８０年营造的１１年生杉木全同胞子代林的试验研究，表明子代林在生长上存在着极显著差异。这些差异主要由遗传引起。一般配合力效应占杉木生长遗传效应的主导地位，特殊配合力占次要地位。产地杂交表现有一定的优势。不同年份间材积生长量和现实增益方面存在密切的相关关系。利用这些差异，可为建立高世代种子园选择优良亲本。     

茶叶儿茶素保健及药理功能研究进展

儿茶素是茶叶诸多保健及药理功能之首要成分,本文将儿茶素诸多的功能总结为"三抗(抗癌、抗衰、抗氧化)"、"三降(降血糖、降血脂、降血压)"及"三消(消毒、消炎、消臭)"等十大功效并对其进行了系统综述.     

Identifying physiological traits associated with improved drought resistance in winter wheat

The association of specific target traits for drought resistance (early flowering, high accumulation of stem water soluble carbohydrate (WSC) reserves, presence of awns and high green flag-leaf area persistence) with yield performance under late-season drought was analyzed utilizing two doubled-haploid (DH) populations derived from crosses between Beaver × Soissons and Rialto × Spark in two seasons 2000/2001 and 2001/2002. The aim was to quantify associations between target traits and yield responses to drought, and to prioritize traits for drought resistance. Flowering time variation had a neutral effect on the absolute yield loss under drought, suggesting there may be a trade-off between water-saving behaviour in the shorter pre-flowering period with early flowering and a reduced capacity to access water associated with a smaller rooting system. The presence of awns also had a neutral effect on yield loss under drought amongst lines of the Beaver × Soissons population. The potential advantages of awns for increasing water-use efficiency and sensible heat transfer responsible for a cooler canopy appeared to be of less significance under moderate droughts in the UK than under severe droughts in other regions worldwide. The value of large stem soluble carbohydrate reserves for drought environments alone could not be confirmed in the UK environment. Stem WSC was positively associated with grain yield under both irrigation and drought. The genetic trait which showed the clearest correlation with the ability to maintain yield under drought was green flag-leaf area persistence. Averaged across years, the positive phenotypic correlation of this trait with yield under drought amongst DH lines of the Beaver × Soissons population (r = 0.49; p ≤ 0.001) indicated the potential use of this trait as a selection criterion for yield under drought. It is suggested that screens for this trait including marker-assisted selection would have value in future breeding programmes aimed at improving yields in high yielding, rainfed environments, but where drought can also be a problem, such as the UK.