菠萝不同月份采收果实品质变化规律研究

以我国菠萝主栽品种‘巴厘’为试材,分析不同月份采收的菠萝果实Vc、可滴定酸、可溶性糖和可溶性固形物的变化,结果表明：不同月份成熟的菠萝果实Vc含量有差异,1～12月呈先降低后升高的趋势,11～4月较高,5～9月较低;可滴定酸含量与Vc含量变化趋势一致,11～3月较高,4～9月较低;不同月份成熟菠萝果实可溶性糖含量变化无明显规律,1、5、6、7、12月较高,其他月份较低;可溶性固形物含量表现出与Vc、可滴定酸含量变化相反的趋势,5～7月较高,其次为9、11,2、3月,可溶性固形物含量最低;各月份果实糖酸比情     

南方根结线虫被穿刺巴斯德芽菌侵染后寿命和生殖相关基因的表达变化

为了探讨南方根结线虫在植物体外被穿刺巴斯德芽菌感染后存活率的变化及感染初期线虫寿命和生殖相关基因的表达情况。首先利用单卵块孵化法对从野外采集的根结线虫进行纯化和分子鉴定。以穿刺巴斯德芽菌孢子体外吸附的南方根结线虫为材料,在显微镜下观察供试线虫的存活情况,每24 h计数一次死亡线虫的条数,总共观察12 d。在被穿刺巴斯德芽菌吸附的第3天收集根结线虫,提取线虫总RNA,采用实时荧光定量PCR检测线虫寿命相关基因cyp-33和生殖相关基因lin-45/mek-2的表达情况。结果表明：通过分子鉴定确认纯化的根结线虫为南方根结线虫;感染了穿刺巴斯德芽菌的南方根结线虫死亡率显著升高;同时在穿刺巴斯德芽菌吸附南方根结线虫的初期,线虫寿命相关基因cyp-33和生殖相关基因lin-45/mek-2的表达水平与对照组相比均下调（p<0.05）。这说明穿刺巴斯德芽菌在吸附南方根结线虫的初期能够促使线虫的存活率降低,并抑制其生殖能力,这可能与基因cyp-33、lin-45和mek-2的调控有关。     

中华鲟幼鱼到达长江口时间新记录

2015年4月16日,在长江口水域监测到1 ind中华鲟(Acipenser sinensis)幼鱼,全长8.10 cm,体长7.00 cm,体质量2.19 g,经形态和分子鉴定,确定为野生中华鲟幼鱼,这是2014年以来在长江口水域监测到的首例野生中华鲟幼鱼。与历史资料相比,该幼鱼到达长江口时间提早约1个月,是中华鲟幼鱼到达长江口的最早新记录。该小规格幼鱼的发现和较早的在长江口水域出现,原因有几种推测:一是长江葛洲坝下产卵场仍然存在中华鲟产卵活动,但产卵时间发生了较大变化;二是在葛洲坝下中华鲟产卵场下游形成了新产卵活动场所,且距离长江口更近。     

被子植物开花时间和花器官发育的表观遗传调控研究进展

成花转换是被子植物生活周期中的关键发育过程,植物通过调控基因表达模式而整合多条内外开花信号实现成花诱导。近几十年来,学者们为阐释植物成花转换的分子机制做了大量的分子遗传学研究。其中,影响植物生长发育的表观遗传修饰是调控成花转换过程的重要分子机制之一。表观遗传调控是植物在适宜环境条件下实现开花诱导和花器官发育的决定性因素。综述了有关开花时间和花器官发育的表观遗传学研究进展,包括染色质重塑、组蛋白甲基化和miRNAs。     

Index-based assessment of agricultural drought in a semi-arid region of Inner Mongolia, China

Agricultural drought is a type of natural disaster that seriously impacts food security.Because the relationships among short-term rainfall,soil moisture,and crop growth are complex,accurate identification of a drought situation is difficult.In this study,using a conceptual model based on the relationship between water deficit and crop yield reduction,we evaluated the drought process in a typical rainfed agricultural region,Hailar county in Inner Mongolia autonomous region,China.To quantify drought,we used the precipitation-based Standardized Precipitation Index(SPI),the soil moisture-based Crop Moisture Index(CMI),as well as the Normalized Difference Vegetation Index(NDVI).Correlation analysis was conducted to examine the relationships between dekad-scale drought indices during the growing season(May–September)and final yield,according to data collection from 2000 to 2010.The results show that crop yield has positive relationships with CMI from mid-June to mid-July and with the NDVI anomaly throughout July,but no correlation with SPI.Further analysis of the relationship between the two drought indices shows that the NDVI anomaly responds to CMI with a lag of 1 dekad,particularly in July.To examine the feasibility of employing these indices for monitoring the drought process at a dekad time scale,a detailed drought assessment was carried out for selected drought years.The results confirm that the soil moisture-based vegetation indices in the late vegetative to early reproductive growth stages can be used to detect agricultural drought in the study area.Therefore,the framework of the conceptual model developed for drought monitoring can be employed to support drought mitigation in the rainfed agricultural region of Northern China.     

Quantitative trait loci mapping of seed colour,hairy leaf,seedling anthocyanin,leaf chlorosis and days to flowering in F2 population of Brassica rapa L.

A diversity arrays technology (DArT) map was constructed to identify quantitative trait loci (QTL) affecting seed colour, hairy leaf, seedling anthocyanin, leaf chlorosis and days to flowering in Brassica rapa using a F₂ population from a cross between two parents with contrasting traits. Two genes with dominant epistatic interaction were responsible for seed colour. One major dominant gene controls the hairy leaf trait. Seedling anthocyanin was controlled by a major single dominant gene. The parents did not exhibit leaf chlorosis; however, 32% F₂ plants showed leaf chlorosis in the population. A distorted segregation was observed for days to flowering in the F₂ population. A linkage map was constructed with 376 DArT markers distributed over 12 linkage groups covering 579.7 cM. The DArT markers were assigned on different chromosomes of B. rapa using B. rapa genome sequences and DArT consensus map of B. napus. Two QTL (RSC1‐2 and RSC12‐56) located on chromosome A8 and chromosome A9 were identified for seed colour, which explained 19.4% and 18.2% of the phenotypic variation, respectively. The seed colour marker located in the ortholog to Arabidopsis thaliana Transparent Testa2 (AtTT2). Two QTL RLH6‐0 and RLH9‐16 were identified for hairy leaf, which explained 31.6% and 20.7% phenotypic variation, respectively. A single QTL (RSAn‐12‐157) on chromosome A7, which explained 12.8% of phenotypic variation was detected for seedling anthocyanin. The seedling anthocyanin marker is found within the A. thaliana Transparent Testa12 (AtTT12) ortholog. A QTL (RLC6‐04) for leaf chlorosis was identified, which explained 55.3% of phenotypic variation. QTL for hairy leaf and leaf chlorosis were located 0–4 cM apart on the same chromosome A1. A single QTL (RDF‐10‐0) for days to flowering was identified, which explained 21.4% phenotypic variation.     

花后前期高温对玉米强弱势籽粒生长发育的影响

采用籽粒离体培养的方法,研究花后高温对玉米强、弱势籽粒的影响。结果表明,高温处理加快了强、弱势籽粒前期的灌浆速率,但降低了中后期的灌浆速率,导致粒重降低,且对弱势粒影响尤为显著,高温处理强、弱势粒成熟期粒重分别比对照低5.8%、17.4%;高温显著降低了籽粒不同灌浆时期的淀粉合成相关酶活性,从而使淀粉含量降低,强势粒的淀粉含量降低幅度小于弱势粒;与对照相比,高温处理后强势籽粒中的3-吲哚乙酸(IAA)和玉米素核苷(ZR)含量显著下降,赤霉素(GA₃)含量则无显著差异,而弱势粒IAA、ZR含量显著降低,但GA₃含量增加,可能是导致弱势粒干重受损较大的原因。     

咸淡组合淋洗对土壤水盐分布特征的影响

为了缓解干旱半干旱地区淡水资源紧缺问题,最大限度地利用浅层地下微咸水,以全部淡水和全部咸水为对照,采用两咸一淡组合淋洗的方法对垂直土柱淋洗后土壤剖面的水、盐分布规律及土壤理化性质的变化进行研究,结果表明在累积入渗量相同的前提下,咸淡组合次序对土壤大孔隙的形成有影响,导致土壤透水性不同,通过入渗进入土壤的总盐量是土壤含盐量的主要影响因素;入渗历时的延长有助于提高土壤剖面脱盐深度,淡-咸-咸的组合次序洗盐效果最好;各种咸淡组合次序均导致20 cm深度处的钠吸附比较初始值增大,尤其是全部咸水入渗会降低土壤的渗透性,有可能导致土壤发生次生盐渍化.该研究为微咸水的田间合理利用提供了依据.     

不同老化时间和收获期对春小麦种子活力的影响

[目的]探明小麦种子在不同收获期下贮藏过程中种子活力变化.[方法]采用高温高湿人工加速老化的方法,对3个不同收获时期的春小麦种子在100;相对湿度和41℃条件下进行人工加速老化,处理时间分别为0、2、4、6、8d,测量发芽率、发芽势、活力指数、平均发芽时间、幼苗干鲜重等指标.[结果]不同收获期下老化2d的各项指标与对照组相比,差异不大,从第4d开始,随着老化时间增长,各相关指标均呈明显下降趋势,在老化第8d时,种子的发芽率最低降至60.33;.[结论]采用种子活力指数结合主要农艺性状可有效评价不同人工老化处理对不同收获期小麦种子活力的影响.人工老化处理这一措施结果显示种子在短时间内受到高温高湿胁迫伤害较轻,老化的时间越长,种子受到的伤害越深,劣变越快.