Responses of plant community to the linkages in plant-soil C:N:P stoichiometry during secondary succession of abandoned farmlands,China

Succession is one of the central themes of ecology;however,the relationship between aboveground plant communities and underground soils during secondary succession remains unclear.In this study,we investigated the composition of plant community,plant-soil C:N:P stoichiometry and their relationships during secondary succession after the abandonment of farmlands for 0,10,20,30,40 and 50 a in China,2016.Results showed that the composition of plant communities was most diverse in the farmlands after secondary succession for 20 and 50 a.Soil organic carbon and total nitrogen contents slightly decreased after secondary succession for 30 a,but both were significantly higher than those of control farmland(31.21%-139.10%and 24.24%-121.21%,respectively).Moreover,C:N ratios of soil and microbe greatly contributed to the changes in plant community composition during secondary succession of abandoned farmlands,explaining 35.70%of the total variation.Particularly,soil C:N ratio was significantly and positively related with the Shannon-Wiener index.This study provides the evidence of synchronous evolution between plant community and soil during secondary succession and C:N ratio is an important linkage between them.     

Quantitative trait loci analysis for root traits in synthetic hexaploid wheat under drought stress conditions

Synthetic hexaploid wheat(SHW), possesses numerous genes for drought that can help breeding for drought-tolerant wheat varieties. We evaluated 10 root traits at seedling stage in 111 F9 recombinant inbred lines derived from a F2 population of a SHW line(SHW-L1) and a common wheat line, under normal(NC) and polyethylene glycol-simulated drought stress conditions(DC). We mapped quantitative trait loci(QTLs) for root traits using an enriched high-density genetic map containing 120 370 single nucleotide polymorphisms(SNPs), 733 diversity arrays technology markers(DArT) and 119 simple sequence repeats(SSRs). With four replicates per treatment, we identified 19 QTLs for root traits under NC and DC, and 12 of them could be consistently detected with three or four replicates. Two novel QTLs for root fresh weight and root diameter under NC explained 9 and 15.7% of the phenotypic variation respectively, and six novel QTLs for root fresh weight, the ratio of root water loss, total root surface area, number of root tips, and number of root forks under DC explained 8.5–14% of the phenotypic variation. Here seven of eight novel QTLs could be consistently detected with more than three replicates. Results provide essential information for fine-mapping QTLs related to drought tolerance that will facilitate breeding drought-tolerant wheat cultivars.     

番茄褪绿病毒在湖南省首次发生

2016年7月在湖南省蔬菜病害调查中发现,4种茄科蔬菜表现出叶脉间褪绿、叶片黄化等症状,疑似被番茄褪绿病毒(Tomato chlorosis virus,To CV)感染,同时叶片背面聚集了大量烟粉虱。采用To CV热激蛋白(heat shock protein 70,HSP70)序列的特异性引物对采集的番茄、茄子、辣椒、马铃薯样品和烟粉虱样品进行RT-PCR检测,均扩增出目标条带,且扩增序列与北京番茄To CV分离物(KC887999.1)部分序列相似度为99.0%,确认采集样品被To CV感染。4种茄科蔬菜To CV的感染率达70%~100%;发病叶片上烟粉虱的带毒率为66.7%~87.5%;鉴定出烟粉虱的生物类型为MED烟粉虱。这是湖南省首次确认该病毒,需要引起关注和加强防范。     

Construction and evaluation of introgression lines and fine mapping of ehd8 from Jinghong common wild rice (Oryza rufipogon)

Heading date is one of the most important traits in rice and regulated by multiple genes. Common wild rice is the ancestor of Asian cultivated rice and harbours abundant genetic diversity. To use wild rice resource in rice breeding, a set of 154 introgression lines (ILs) covering 93% of the genome of Jinghong common wild rice was constructed in the background 'Teqing', using 208 simple sequence repeat markers evenly distributed on 12 chromosomes. Among the ILs, the line JIL64 displayed late heading independent of photoperiod. Genetic analysis using the two F₂ populations crossed ''Teqing'/JIL64 and JIL64/'Teqing' revealed that late flowering was controlled by a recessive gene on chromosome 8 (designated early heading date 8, ehd8), and ehd8 was fine mapped to the 50‐kb region flanked by markers RM22221 and 64Indel4. Sequencing and qRT‐PCR demonstrated that LOC_Os08g01410 and LOC_Os08g01420 were deleted in JIL64 and may be associated with the late heading of Jinghong common wild rice. These findings lay a practical foundation for characterizing ehd8, and the ILs help to mine genes from Jinghong common wild rice.     

基于UHPLC-Q-TOF/MS的不同产地普洱生茶化学成分差异研究

为了更加全面地了解产地对普洱生茶品质与化学成分的影响,本研究选取来自临沧市、普洱市、西双版纳州三大产区12个茶山(自然村)的普洱生茶样品,采用超高效液相色谱-四级杆-飞行时间质谱(UHPLC-Q-TOF/MS)对不同产地普洱生茶的非挥发性代谢物表型进行了研究。结果表明:不同产地普洱生茶的化学成分在含量上具有较大差异,且具有明显的产地特征。采用主成分分析,可以对来自西双版纳自治州(包括勐腊县、勐海县、景洪市)、普洱市、临沧市3个地级行政区的普洱生茶进行有效区分,也可以对来自普洱茶产区的东南、西南、西北3个区域的普洱生茶进行有效区分。进一步鉴定了普洱生茶中79种主要成分,并对其在12个茶山(自然村)的普洱生茶中的含量分布,以及与不同产地普洱生茶滋味品质的关系进行了分析。本研究表明,基于UHPLC-Q-TOF/MS的茶叶非挥发性化学成分轮廓可以作为普洱生茶产地判别的依据。     

文冠果优良无性系授粉组合选择及结实性状分析

  目的  探究文冠果Xanthoceras sorbifolium优良无性系最佳授粉组合，提高其坐果率、种实产量，为科学配置授粉树及优良种质资源无性系化推广提供参考。  方法  以文冠果5个优良无性系为材料，进行花期物候观测、柱头可授性及花粉活力检测。进行控制授粉，分析各授粉组合受精率、坐果率、种实产量及种实性状。  结果  ① 5个无性系开花时间在4月27日至5月14日。②雌能花开花当天及花后1 d柱头可授性较强。③雄能花初开放和完全开放当天花粉活力较高。④综合考虑各授粉组合受精率、最终坐果率、产量及种实性状得出，10号无性系较佳授粉组合为10×16、10×119，14号、15号、16号最佳授粉组合分别为14×15、15×16、16×15，10号、14号、15号、16号均不适合做119号的授粉无性系。  结论  科学的授粉树配置可以提高文冠果坐果率及种实产量。     

浙江省油菜花期降水量风险评估

对浙江省66个县市(区)1971—2014年油菜花期降水量及油菜产量资料进行统计分析,并基于信息扩散的风险评估模型,对浙江省油菜花期降水量在各级降水量下的超越概率进行计算分析,评估各地油菜花期面临的旱涝风险;同时分析了浙江省油菜花期各级降水量风险值与油菜产量变化之间的关系。结果表明:油菜花期降水量严重过剩的风险高值区主要位于浙西南地区,降水量短缺风险高值区主要位于浙江省沿海岛屿及宁波的部分县市;浙江省油菜花期降水量短缺基本可以通过灌溉得到改善,但油菜减产与花期降水量过多显著相关,油菜花期降水量300 mm是油菜是否减产的阈值。该结果可为油菜种植合理布局及农业保险政策提供科学依据。     

植物乳杆菌野生质粒分析及其提取方法的优化

乳酸菌质粒提取研究具有很长的历史。目前已有多个有效的乳酸菌质粒提取方法被报道，其中多数以乳酸球菌为研究对象，而植物乳杆菌质粒提取有效方法报道较少。该研究以植物乳杆菌为研究对象，通过对比分析并优化已报道的乳酸菌质粒提取方法，得到了高效且适于平台期植物乳杆菌野生质粒的提取方法。通过该方法进一步分析了植物乳杆菌野生质粒数和高拷贝质粒，为后续构建植物乳杆菌表达系统所需供体质粒和受体菌株提供了重要依据。     

关中-天水经济区人类活动对植被覆盖变化的影响

为探究植被覆盖变化及人类活动对改善关中地区及西北地区的生态环境影响,利用植被覆盖和地表温度数据,结合Sen趋势与Mann-Kendall检验分析关中-天水经济区2001—2016年的植被覆盖变化趋势,并根据估算的土壤湿度因子,应用残差法评价人类活动对植被覆盖变化的影响程度及影响方向。结果表明:1)从时间变化维度来看,2001—2016年关中-天水经济区植被覆盖变化总体呈良好趋势,且整体表现为在不断波动中递增,表明关天经济区进行的生态环境建设工程正在慢慢凸显它的生态效应。2)从空间变化维度来看,关中-天水经济区植被覆盖显著增长的区域面积占35.87%,主要集中在研究区南北两侧。而显著下降的面积区域占3.21%,主要分布在城市中心,即经济发展活跃的地区,如西安市区,宝鸡市区,天水市区,铜川市区等。3)关中-天水经济区植被覆盖受自然因素影响较小,受其他因素影响大。其正相关区域占13.43%,不显著相关区域占85.26%。4)关中-天水经济区人类活动对植被覆盖变化的正作用大于负作用。其中,正作用区域主要分布在研究区北部和东南地区,其主要原因是人类活动不频繁,建设生态屏障、加强退耕还林、三北防护林保护以及水土保持等生态工程促进植被NDVI增长。负作用区域主要分布在渭河沿线、经济活动较高地区,其主要原因有:人类活动频繁、过度城市化、工业化等抑制植被生长。5)植被覆盖的增长和下降区域与人类活动对植被影响的正作用和负作用区域大致相同。这也从侧面反映了关天经济区植被覆盖情况受人类活动影响大。总之,在负作用区域,在经济建设发展的同时也要注重植被建设、以及对植被乃至生态环境的保护。