Intestinal Microbiota in Large Yellow Croaker,Larimichthys crocea,at Different Ages

The polymerase chain reaction–denaturing gradient gel electrophoresis (PCR‐DGGE) of 16S ribosomal RNA gene was used to investigate bacterial communities in the intestines of large yellow croaker at six different ages (12 d, 18 d, 26 d, 40 d, 3 mo, and 1 yr old) as well as within the corresponding feed and culture water. In addition, Illumina Miseq sequencing was utilized to compare intestinal microbiota between 12‐d‐old and 1‐yr‐old individuals. PCR‐DGGE results revealed that the culture water had the highest bacterial diversity, followed by the feed, while the intestines had the lowest diversity. The intestinal microbiota at six ages changed severely; however, the change did not follow any trend. The large yellow croaker intestines harbored specific bacterial communities that differed from those in both feed and water. Illumina Miseq sequencing results revealed that the diversity of intestinal bacteria in 12‐d‐old fish was higher than that in 1‐yr‐old fish, and the bacterial composition differed significantly between them. γ‐Proteobacteria and Pseudoalteromonas supplied the most abundant phylum and genus in the 12‐d‐old fish intestine. However, in the 1‐yr‐old fish intestine, Firmicutes and Clostridium were the most dominant, respectively. The study may contribute to a better understanding of gut microbiota and dynamics of the large yellow croaker and the relationship with their surrounding environment.     

环西湖不同树龄古樟树生理特性及复壮对比

樟树是杭州市市树,也是环西湖古树中最主要的树种之一。为了加强环湖景区古樟树的保护管理和救治复壮,促进滨湖景观的可持续发展,通过实地调查,并对古樟树不同树龄及复壮前后叶片保护酶进行测定研究。结果表明：树龄200~299年和300~499年的古樟实际年龄与生理年龄有显著差异,300~499年的古樟生长势优于200~299年古樟,生长代谢与100~199年古樟相似;500年以上古樟的生长势明显衰弱。叶片黄化则会导致POD活性下降。复壮对古樟树生长势恢复起到较为显著的效果。经病虫害防治、注干施肥、立地环境改善、树洞修补等措施复壮的古樟叶绿素含量和SOD活性上升,MDA含量和POD活性下降。因此,做好复壮前后古樟各项生理指标的测定及日常动态观测记录,有利于进一步提升环西湖一带古树名木的养护管理水平。     

不同年产度杂交水稻种子活力和田间生产性能的研究

本文研究了杂交水稻汕优6号新种子和不同年产度陈种子的活力及其田间生产性能。结果表明,不同年产度种子的活力有明显差异,种子活力随贮藏时间的延长而下降。不同年产度种子的田间生产性能随种子贮藏时间的延长呈下降趋势。1年、2年、3年陈种的产量比新种分别下降0.9%、8.0%和5.4%,生育期比新种分别缩短1天、2天和4天。这些说明,1年陈种有较大的利用价值,在新种不足的情况下,可用一年陈种来补偿。不同年产度种子活力与田间早期生产性能有显著相关性,但与田间后期生产性能无显著相关性。因此可用室内活力测定指标来预测种子的田间出苗性能,但不能预测产量。     

不同树龄橡胶树林地土壤有机碳含量与储量特征

研究幼林早期(2龄)、幼林晚期(7龄)、开割树(16龄)和老龄即将更新树(30龄)4种不同树龄橡胶树林地的土壤有机碳含量与储量特征.结果表明:(1)不同树龄橡胶树林地各土壤层次土壤有机碳含量变化不大,但普遍表现为表层土壤(0～15 cm土层)有机碳含量高于平均值,下层土壤(45～60cm土层)有机碳含量低于平均值,中间两层的(15～30cm土层、30～45 cm土层)变化不大,在平均值的上下浮动;(2)不同树龄橡胶树林地土壤有机碳含量介于6.03～7.78g/kg之间,相互间存在显著差异,高低排序为幼林晚期(7龄)老龄即将更新树(30龄)幼林早期(2龄)开割树(16龄);(3)胶林有机碳储量主要决定于其土壤有机碳含量和土壤容重,不同树龄橡胶树林地土壤有机碳储量介于61.33～74.29t/hm2之间.相互间存在差异,高低排序为老龄即将更新树(30龄)幼林晚期(7龄)幼林早期(2龄)开割树(16龄).     

Climatic significance of glacier retreat and rockglaciers re-assessed in the light of cosmogenic dating and weathering rind thickness in Clarée valley (Briançonnais,French Alps)

Recent advances in geochronology provide opportunities to identify the glacial and periglacial sequences in mountain area. In this paper, we focus on the Upper Durance catchment (Southern French Alps), in the Clarée valley, where no absolute chronological benchmark was defined. Glacial remnants and periglacial features were investigated, integrated within a chronological scenario thanks to relative (weathering rind thickness) and absolute (CRE technique) dates. We find evidence of the existence of a Late-Glacial valley glacier, that has never been reported before. Then the upper valleys became ice-free during a period corresponding to the Early-Holocene Climate Optimum, whereas two sequences of cirque glaciation are identified during the second half of the Holocene. We also show evidence of three main generations of rockglaciers, which also mainly developed during the second half of the Holocene, probably at the end of the Subboreal period. The location and the altitudes of rockglaciers are strongly dependent on the geomorphic setting (especially the location of the sediment sources), hence complicating their palaeo-climatic interpretations.     

不同秧龄对机插连作晚稻宁84和甬优538秧苗素质和产量的影响

以宁84和甬优538为试验材料,研究了不同秧龄处理对机插连作晚稻秧苗素质、出叶情况、茎蘖动态及产量的影响。结果表明,随着秧龄的增加,秧苗素质明显变差,主茎叶数逐渐减少,株高变矮,穗长变短,产量降低。宁84和甬优538秧龄23 d、28 d的处理实际产量比秧龄18 d的处理分别降低0.86%、12.80%和2.67%、14.71%。随着秧龄的延长,2个品种的高峰苗数逐渐增加,宁84的成穗率随秧龄的延长而增加,甬优538的成穗率随秧龄的增加而降低。通过品种间的比较发现,相同秧龄条件下,宁84秧苗素质差于甬优538,但移栽后高峰苗数和成穗率高于甬优538。     

岩溶石漠化区李树林土壤岩溶作用强度及碳汇效应

石漠化地区不同种植年限人工经济林下土壤岩溶作用强度研究不仅关系到岩溶碳汇估算,也关系到岩溶区陆地碳源/汇的准确评估。利用标准溶蚀试片法研究了典型石漠化治理区不同种植年限李树人工林土下石灰岩溶蚀速率。结果表明:不同种植年限李树人工林土下石灰岩溶蚀量在42～136.3t/(km²·a)之间,折算成单位面积碳汇量则在5～16.4 t/(km²·a)之间,种植年限对土下石灰岩溶蚀速率具有显著影响,基本表现为植被生长初始和达到稳定阶段时的溶蚀速率较大,此时的碳汇潜力也较大。因此,在石漠化治理的过程中种植人工经济树种,在岩溶区地表森林系统的增汇过程发生的同时,地下也同步发生着类似的增汇过程。因此,在岩溶区碳循环潜力与评价研究中必须考虑岩溶作用。     

鲁北洼羊羔羊的屠宰率相关性研究

在毛皮生产最佳时期对鲁北洼羊羔羊进行了屠宰率、体尺及体重等测定，分析结果表明：①屠宰率与日龄相关显著（Ｐ＜０．０５），其回归方程为ｙ＝５０．１１－０．０５ｘ；②屠宰率与体高（ｘ１）、体长（ｘ２）、胸围（ｘ３）、十字部高（ｘ４）呈负相关；③屠宰率的估测公式为ｙ＝５４．５９０７－０．０１８０ｘ１－０．００８３ｘ２－０．００６７ｘ３－０．０１８０ｘ４（Ｐ＜０．０５）。     

不同月龄荷斯坦奶公犊肉品质的比较研究

[目的]对不同月龄的荷斯坦奶公犊肉品质进行比较研究,探索奶公犊牛肉内在品质,为解决肉牛源不足加快奶牛肉用化提供参考依据.[方法]在相同的营养模式下随机选取荷斯坦奶公犊12、15、18月龄及淘汰荷斯坦牛各3头进行屠宰,取右半边胴体的背最长肌作为肉品质试验样品,分别对肉品质的感官、理化及加工指标进行分析.[结果]干物质、粗蛋白、粗脂肪、失水率、系水力、熟肉率12月龄荷斯坦奶公犊分别为23.12;、18.75;、4.28;、21.05;、72.62;、64.48;;15月龄的分别为23.94;、19.22;、8.11;、20.96;、72.44;、62.21;;18月龄的分别为26.30;、20.14;、10.04;、22.34;、69.69;、61.52;;淘汰荷斯坦牛分别为25.07;、19.31;、11.54;、25.03;、67.03;、59.50;.18月龄荷斯坦奶公犊肉色、大理石纹、嫩度等指标好于其他三个时期,氨基酸含量及组成结构处于比较理想的状态,但各月龄阶段18种游氨基酸处于动态变化过程.[结论]随着月龄的增长,各阶段肉品质指标除灰分、pH以外存在显著性差异,综合各项指标18月龄荷斯坦奶公犊肉品质最佳.     

古树名木研究概述

概述了我国古树名木的研究现状,包括古树年龄测定、衰老机理、复壮技术、地理信息系统等方面,提出了今后的研究方向。