烟草水分胁迫研究进展

综述了烟草水分胁迫与烟株生长发育、烟株生理变化以及产、质量的关系,并展望了今后的研究方向.     

全面建设小康社会的水利发展目标

根据党的十六大提出的全面建设小康社会的发展目标 ,结合新中国成立 5 0多年来我国水利建设的现状 ,分析我国当前水利建设面临的形势和全面建设小康社会对水利建设的要求 ,提出了全面建设小康社会的水利发展 10大目标 :至 2 0 2 0年 ,全国总用水量为 6 5 0 0亿m3;水旱灾害损失占GDP的比例降为 2 0 % ;农业用水占总用水量的比例降为 6 0 % ;城乡供水普及率达 75 % ;水功能区水质达标率为 75 % ;水土流失治理率达 6 5 % ;生态环境用水保障程度达 70 % ;万元GDP用水量为2 0 0m3;水管理信息化水平达 80 % ;大、中专以上学历水管理人员比例达 80 % .综合实现程度达75 % .     

现状防御条件下历史极端大旱重演影响分析——以明崇祯大旱为例

开展历史典型场次特大干旱事件重演研究,能够为极端状况下的干旱灾害防御提供参考,具有重要的战略意义。本文提出了历史特大干旱重演影响分析方法,并以明崇祯大旱为例,开展现状防御条件下重演情景分析,估算一旦发生明崇祯大旱对供水、粮食以及经济的可能影响。研究结果表明:在现状自然地理和水利工程条件下,若发生类似明崇祯大旱,核心旱区9省市连续7年年平均缺水率为21.9%,最高为38.7%;年平均粮食减产率为27.7%,最高为39.2%;年平均因旱直接经济损失占本区域GDP比例为5.3%,最高为11.1%;占全国GDP比例年平均达到2.2%,最高为4.53%。可见,一旦发生类似历史上的极端干旱,严重缺水将会对供水安全、粮食安全和经济安全造成重大威胁,因此需要引起高度重视,做好巨灾风险应对准备。     

云南中北部地区1954-2012年干旱评价研究

利用云南中北部地区6个气象站点1954-2012年资料,选用标准化指数计算各站点干旱指数,统计分析了云南中北部地区1954-2012年发生干旱的年份及发生不同干旱的频次。研究结果表明:1临沧站出现干旱的年份较多,但蒙自站出现极端干旱的年份明显高于其他5站;2各站点在不同季节出现干旱的频次不同,其中腾冲在春季相比于其他5站,发生干旱的频率较高35.6%,临沧站在夏季和冬季发生干旱频率均较大,分别为35.6%和37.9%,蒙自站在秋季发生干旱频率最大,为34.8%。研究成果可为云南中北部地区的干旱评价分析和水资源保护提供一定的参考价值。     

干旱指数在四川省的适用性分析

干旱灾害频发严重制约着四川省的农业发展,为合理分析四川省干旱情况,干旱指数的选择尤为重要。本文基于四川省39个气象站点1960年-2013年的气象资料,分别计算1961年、1994年、2006年和2009年-2010年各站点相对湿润指数M、气象干旱综合指数CI、标准化降水指数SPI和标准化降水蒸散指数SPEI,利用Arcgis反距离插值法进行空间插值,并与中国气象灾害大典记录的四川省典型年干旱情况进行对比分析,进而评价四种干旱指数在四川省的适用性。结果表明:对于1961年夏旱,M指数和CI指数均表现出无旱或轻旱,SPI指数结果较实际情况偏小,SPEI指数监测出了干旱的重灾区,效果在四个干旱指标中最好;1994年夏伏旱,M指数监测结果偏小;CI指数出现了空报,对川东地区和川西高原的监测结果偏小,SPEI指数在达县、巴中一带结果偏小,而SPI指数在成都、绵阳一带的结果偏小。2006年伏旱,M指数监测结果偏小;CI指数比M指数效果稍好,但结果仍然偏小;SPI指数和SPEI指数监测出的干旱特征与实际一致;2009年-2010年的冬春连旱,SPEI指数效果最好,M指数次之,SPI指数效果最差。SPEI指数最能反映四川省典型干旱年干旱的空间分布特征。     

渭河流域主要控制断面旱限流量确定

旱限流量是评估河流干旱等级的水文特征指标,是启动抗旱应急响应等级的重要依据,是做好抗旱水量应急调度的重要基础。依据水文断面下游主要取用水需求,分析计算各取水口取用水量,以取用水量与河道生态流量之和作为初值,综合确定旱限流量。通过对渭河流域主要控制断面旱限流量的分析研究,确定拓石、魏家堡、咸阳、临潼、华县的旱限流量分别为:16.0、11.0、10.0、50.0、12.0 m3/s,为科学合理判断水文干旱等级及进行抗旱指挥决策提供可靠依据。     

Candidate Genes and Pathways in Rice Co-Responding to Drought and Salt Identified by gcHap Network

Drought and salinity stresses are significant abiotic factors that limit rice yield. Exploring the co-response mechanism to drought and salt stress will be conducive to future rice breeding. A total of 1748 drought and salt co-responsive genes were screened, most of which are enriched in plant hormone signal transduction, protein processing in the endoplasmic reticulum, and the MAPK signaling pathways. We performed gene-coding sequence haplotype (gcHap) network analysis on nine important genes out of the total amount, which showed significant differences between the Xian/indica and Geng/japonica population. These genes were combined with related pathways, resulting in an interesting mechanistic draft called the ‘gcHap-network pathway’. Meanwhile, we collected a lot of drought and salt breeding varieties, especially the introgression lines (ILs) with HHZ as the parent, which contained the above-mentioned nine genes. This might imply that these ILs have the potential to improve the tolerance to drought and salt. In this paper, we focus on the relationship of drought and salt co-response gene gcHaps and their related pathways using a novel angle. The haplotype network will be helpful to explore the desired haplotypes that can be implemented in haplotype-based breeding programs.     

Effect of Trichoderma asperellum on Wheat Plants’ Biochemical and Molecular Responses,and Yield under Different Water Stress Conditions

Eight Trichoderma strains were evaluated for their potential to protect wheat seedlings against severe (no irrigation within two weeks) water stress (WS). Considering the plant fresh weight and phenotype, T. asperellum T140, which displays 1-aminocyclopropane-1-carboxylic acid deaminase activity and which is able to produce several phytohormones, was selected. The molecular and biochemical results obtained from 4-week-old wheat seedlings linked T140 application with a downregulation in the WS-response genes, a decrease in antioxidant activities, and a drop in the proline content, as well as low levels of hydrogen peroxide and malondialdehyde in response to severe WS. All of these responses are indicative of T140-primed seedlings having a higher tolerance to drought than those that are left untreated. A greenhouse assay performed under high nitrogen fertilization served to explore the long-term effects of T140 on wheat plants subjected to moderate (halved irrigation) WS. Even though all of the plants showed acclimation to moderate WS regardless of T140 application, there was a positive effect exerted by T. asperellum on the level of tolerance of the wheat plants to this stress. Strain T140 modulated the expression of a plant ABA-dependent WS marker and produced increased plant superoxide dismutase activity, which would explain the positive effect of Trichoderma on increasing crop yields under moderate WS conditions. The results demonstrate the effectiveness of T. asperellum T140 as a biostimulant for wheat plants under WS conditions, making them more tolerant to drought.     

OsHsfB4b Confers Enhanced Drought Tolerance in Transgenic Arabidopsis and Rice

Heat shock factors (Hsfs) play pivotal roles in plant stress responses and confer stress tolerance. However, the functions of several Hsfs in rice (Oryza sativa L.) are not yet known. In this study, genome-wide analysis of the Hsf gene family in rice was performed. A total of 25 OsHsf genes were identified, which could be clearly clustered into three major groups, A, B, and C, based on the characteristics of the sequences. Bioinformatics analysis showed that tandem duplication and fragment replication were two important driving forces in the process of evolution and expansion of the OsHsf family genes. Both OsHsfB4b and OsHsfB4d showed strong responses to the stress treatment. The results of subcellular localization showed that the OsHsfB4b protein was in the nucleus whereas the OsHsfB4d protein was located in both the nucleus and cytoplasm. Over-expression of the OsHsfB4b gene in Arabidopsis and rice can increase the resistance to drought stress. This study provides a basis for understanding the function and evolutionary history of the OsHsf gene family, enriching our knowledge of understanding the biological functions of OsHsfB4b and OsHsfB4d genes involved in the stress response in rice, and also reveals the potential value of OsHsfB4b in rice environmental adaptation improvement.