天然橡胶（Natural rubber）是一种生物高分子聚合物，由于具有独特的理化性质而成为重要的工业原料及不可替代的战略物资。巴西橡胶树（Hevea brasiliensis (Willd. ex A. Juss.) Müll. Arg.）是目前商业化天然橡胶的唯一来源，主要生长在东南亚热带及亚热带地区的种植园中。然而，目前巴西橡胶树的产量难以满足急剧增长的全球工业对天然橡胶的迫切需求。以石油为加工原料的合成橡胶（Synthetic rubber）部分补充天然橡胶产量的不足，但其工业性能无法比拟天然橡胶。因此，亟需开发具有更广泛环境适应性的天然橡胶新作物。本文综述了园艺植物-橡胶草（Taraxacum kok-saghyz Rodin）和莴苣（Lactuca L. species），木本植物-银胶菊（Parthenium argentatum A. Gray）和杜仲（Eucommia ulmoides Oliv.）以及其它有生产天然橡胶潜力的植物的研究进展。本综述以基因组学、转录组学、蛋白质组学和代谢组学等多维组学研究，以及天然橡胶生物合成分子机制为重点，讨论了基于现代生物技术的多维整合策略在解析天然橡胶生物合成机制方面的广阔前景，为加速天然橡胶新作物的培育提供借鉴。

早花能促进美洲南瓜早熟和高产，并能拮抗生物和非生物胁迫，是美洲南瓜重要的农艺性状。在本研究中，美洲南瓜自交系‘19’的第一雌花开花天数明显少于自交系‘113’，表现为稳定的早花性状。遗传分析表明，第一雌花开花天数是一个可遗传的数量性状，受多基因控制。采用QTL测序结合连锁分析的方法，在第4、11和20号染色体上鉴定出3个用于第一雌花开花天数的QTL。为了验证这一结果，利用不同环境条件下生长的F₂群体，开发InDel标记对第一雌花开花天数进行QTL定位分析。利用R/qtl软件的复合区间作图方法，在所有环境条件下均鉴定出1个主位点，位于20号染色体117 kb的候选区域。通过基因注释、基因序列比对和qRT-PCR分析，发现编码环指蛋白的Cp4.1LG20g08050基因可能是一个对美洲南瓜早花起相反调控作用的候选基因。总之，本研究结果为更好地认识美洲南瓜早花性状，为美洲南瓜的早花育种策略奠定了基础。

本文考察了中国农户参与合作社和农业技术采纳行为对其经济福利的影响。基于中国15个省份396个农户的微观调查数据，采用双选择模型(DSM)修正由可观测和不可观测因素引起的样本选择偏差，并采用倾向评分匹配(PSM)方法进行反事实分析，以计算农业收入差异。研究结果表明，相比不参与农民合作社、不采纳农业技术而言，农户参与农民合作社、采纳农业技术的农业收入分别增加2.77%和2.35%。有趣的是，与高收入农户相比，低收入农户参与农民合作社、采纳农业技术的农业收入分别高出5.45%和4.51%，且影响更为显著。这表明农民合作社和农业技术能够提升农户经济福利。在此基础上，本文进一步提出了相应的政策建议。

Traditional agricultural systems have contributed to food and livelihood security. Rice-crab coculture (RC) is an important eco-agricultural process in rice production in northern China. Recognizing the soil fertility in RC may help develop novel sustainable agriculture. Soil carbohydrates are important factors in determining soil fertility in different culture modes. In this study, soil carbohydrates were analyzed under three different culture modes including rice monoculture (RM), conventional rice-crab coculture (CRC) and organic rice-crab coculture (ORC). Results showed that the contents of soil organic carbon and carbohydrates were significantly higher in the ORC than those in RM. The increasing effect was greater with increased organic manure. Similar tendency was found in CRC, but the overall effect was less pronounced compared with ORC. Carbohydrates were more sensitive to RC mode and manure amendment than soil organic carbon. Compare to RM, the (Gal+Man)/(Ara+Xyl) ratio decreased in all the RC modes, indicating a relative enrichment in plant-derived carbohydrates due to the input of crab feed and manure. While the increasing (Gal+Man)/(Ara+Xyl) ratio in ORC modes with increased organic manure suggested that crab activity and metabolism induced microbially derived carbohydrates accumulation. The lower GluN/MurA ratio in ORC indicated an enhancement of bacteria contribution to SOM turnover in a short term. The findings reveal that the ORC mode could improve the quantity and composition of soil carbohydrates, effectively, to ensure a sustainable use of paddy soil.

O3 is not only greenhouse gas but also a primary gaseous contaminant in the atmosphere. It has long-lasting effects on crop growth, yield and quality, and brings a series of ecological and environmental problems. A free-air controlled enrichment (FACE) system was applied to study the effect of elevated ozone concentration on activities of key enzymes of starch synthesis of Yangmai 16 in 2009-2010. The main-plot treatment had two levels of O3: ambient level (A-O3) and 50% higher than ambient level (E-O3). The main results were that accumulation rate of amylose, amylopectin and starch were represented in a single peak curve, and their content and accumulation amount rose gradually. The O3 elevation decreased the accumulation rate of amylose, amylopectin and starch amylase, reduced the accumulation amount of amylopectin and starch, and decreased the content of amylopectin and starch, but increased the content of amylose. With the increase of O3 concentration, the enzyme activity of grain granule-bound starch synthase (GBSS), soluble starch synthase (SSS) and starch branching enzyme (SBE) decreased after anthesis. The activities of GBSS and SSS had highly significant correlations with amylose, amylopectin and starch accumulation rate, and the activity of SBE had significant correlations with these items. So the O3 elevation decreased the activity of key enzymes of starch synthesis, which led to the variation of starch synthesis.