峨眉山野生茶树资源农艺性状多样性分析

为挖掘峨眉山野生茶树和群体种中的优良资源,利用因子分析、聚类分析和感官审评等方法,对峨眉山40份野生茶树种质资源农艺性状进行遗传多样性分析和资源评价。结果表明,峨眉山茶树种质资源丰富,且多以灌木型为主;18个芽叶形态性状的变异系数为7.70%~60.99%,变异系数最大的性状是芽叶色泽(60.99%)。因子分析表明,18个芽叶形态性状综合为6个公因子,前6个公因子的特征值大于1且累计贡献率达80.74%,主要代表性指标为叶片大小、叶片锯齿和叶面特征等。聚类分析将研究材料分为5个大的类群,显示了复杂的亲缘关系和丰富的遗传多样性。适制性研究表明,初步筛选的11份种质资源制绿茶适制性较好,感官审评总分在92分以上,大体表现为香气鲜香带花香、清香高长带花香或栗香浓郁带花香,滋味鲜爽、鲜甜或鲜浓醇。     

水稻粒宽突变体gw87的基因定位及候选基因分析

【目的】对水稻粒宽突变体gw87（grain width 87）进行表型鉴定、遗传分析、基因定位及候选基因分析,为探明该基因调控水稻籽粒大小的分子机制及应用潜力奠定基础。【方法】利用甲基磺酸乙酯诱变籼稻恢复系材料676R,获得一份籽粒宽度和千粒重显著增加的突变体gw87。对该突变体进行表型观察、农艺性状调查及外源油菜素内酯（BL）敏感性、叶绿素含量、光合参数测定,了解其表型特征及生理特性。调查gw87与676R杂交F₁的表型和F₂群体的分离情况,分析其遗传行为;选取该群体中的突变植株进行高通量测序,并利用gw87与粳稻品种日本晴杂交的F₂代作为定位群体,通过MutMap分析和分子标记定位,遴选候选基因并进行DNA和cDNA测序验证。利用qRT-PCR分析gw87和676R中BR合成途径基因OsDWARF4、D11和D2的表达差异。【结果】与野生型亲本676R相比,gw87突变体的株高降低,节间缩短,其中,倒一节间长度缩短最大,并呈现出扭曲的形态;叶片长度减少,宽度增加;单株有效穗数、主穗穗长和结实率显著降低,但籽粒宽度和千粒重显著增大。BL敏感性试验显示,gw87突变体幼苗对外源BL的敏感性降低。光合色素和光合参数测定表明,gw87光合色素含量增加,光合速率也有所增加。遗传分析表明gw87的突变性状是由1对隐性核基因控制。MutMap分析显示gw87突变基因位于第5染色体中部,在该染色体区域仅有1个碱基突变引起编码氨基酸变化;分子标记连锁分析表明该突变基因位于InDel标记X2和X3之间约101 kb的染色体区域;综合这两方面分析结果,最后遴选出gw87候选基因是编码一个含有AP2/EREBP DNA绑定结构域的转录因子基因LOC_Os05g32270。对该候选基因进行DNA和cDNA测序验证,发现gw87突变体中该基因DNA的第1 041位的碱基由G突变为A,导致与该位点相邻的76 bp内含子序列被剪接为外显子,引起阅读框移码,蛋白翻译提前终止。qRT-PCR分析显示gw87突变体中BR合成途径基因的表达量显著上调,表明gw87突变体中BR信号减弱。【结论】gw87是smos1、shb、rla1、ngr5的新等位突变体,但与这些突变体表型不同,gw87籽粒的宽度和千粒重显著增加,可能是LOC_Os05g32270的突变位点不同,导致其编码蛋白的功能活性不同所造成。     

增密减氮对弱筋小麦‘宁麦13’产量和品质的影响

为实现弱筋小麦优质稳产,解决当前弱筋小麦存在品质稳定性差的问题。本试验以弱筋小麦‘宁麦13’为试材,结合方差分析等方法研究增密减氮对弱筋小麦的产量、群体质量指标以及籽粒品质的影响。结果表明,在240 kg/hm²施氮水平条件下,随着密度的增加,小麦LAI、干物质积累量均呈先增加后下降的趋势,密度超过240×10⁴/hm²会导致LAI、干物质积累量、产量下降。在240×10⁴/hm²密度条件下,施氮量超过240 kg/hm²会导致小麦叶面积指数、SPAD值、花后干物质积累量和产量下降。适当的增密减氮有利于提高弱筋小麦的优质稳产,而过量增密减氮则会导致小麦产量下降,品质不稳定。为实现产量和品质的最优化,生产上推荐采用种植密度为240×10⁴/hm²,施氮量为180 kg/hm²,氮肥运筹为7:1:2:0的栽培模式。     

Collembola in ecotoxicology—Any news or just boring routine?

Despite the uncontested significance of soils for human nutrition and drinking water quality, the majority of ecotoxicological testing is confined to aquatic test systems. Among the standardised tests for soils, the reproduction test with the springtail Folsomia candida is among the most widely used ones. First steps towards its standardisation were undertaken in the late 1980s. Here we review major advances that have been made since then, with respect to mechanistic, pragmatic and ecological aspects. Specifically we address the ecological relevance of any modifications of the standardised tests. We introduce a miniaturised version of the reproduction test which allows reducing the amount of soil per test unit to one third and the number of synchronised individuals to 40% as compared to the standard test. In addition, we developed an assay using Collembola eggs instead of synchronised adults. First results of a three-species test indicate that the presence of other species may affect choice behaviour. We point out a potential biased view of existing ecotoxicological data with Collembola due to the fact that most results refer to metal contamination. Finally, recommendations for future research are given, with special reference to avoidance and microcosm tests involving Collembola.     

Maize harvest index and water use efficiency can be improved by inhibition of gibberellin biosynthesis

Possibilities to improve maize harvest index and nutrient utilization efficiency by application of plant growth regulators were investigated. In container experiments, the effects of different growth regulators on the development of the maize (Zea mays L.) cultivars Pioneer 3906 and Fabregas were tested. Paclobutrazol (PAC) and chlorocholine chloride (CCC), two inhibitors of gibberellin biosynthesis, as well as gibberellic acid (GA₃) were applied at growth stage V5. Three weeks after application of PAC, shoot growth of both maize cultivars was strongly affected with a significant decrease in plant height in the PAC treatment by 44% and 36% for Pioneer 3906 and Fabregas, respectively. The growth‐retarded plants had higher leaf areas and reduced transpiration rates. The higher shoot growth after GA₃ application was accompanied by a reduction in leaf area and an increase in transpiration rate during 1 week before anthesis. CCC treatment showed no significant effects on plant height, leaf area and transpiration rate. The PAC‐treated cultivar Pioneer 3906 produced several cobs per plant, which were mainly barren at maturity. However, PAC application to Fabregas resulted in just one cob per plant with good kernel development and a grain yield, which was not significantly reduced in comparison with the control. With this similar grain yield in combination with a straw yield decrease of 32%, the harvest index was significantly improved by 12%. In addition, with PAC‐treated Fabregas plants, a 19% increased water use efficiency of the grain (WUE_grain) during the critical period of kernel setting was achieved. In this maize cultivar, CCC application also improved harvest index by 5%, but no effect on WUE_grain occurred. GA₃ treatment decreased harvest index of both maize cultivars, and it either reduced WUE_grain (Pioneer 3906) or showed no effect (Fabregas). Utilization efficiencies of N, P and K were not increased with growth regulator application, even in the PAC‐treated Fabregas plants with a significantly improved allocation of assimilates to the grain, mirrored by the higher harvest index. The results indicate that fertilizer applications must be adjusted to the reduced demand of growth‐retarded plants, most likely leading to higher nutrient utilization efficiencies.     

相变材料在绿色储粮中的应用探讨

相变材料能够储存或释放显热,在熔化或凝固过程中虽然温度不变但吸收的潜热却相当大。根据相变材料可以吸收环境热能并在需要时向环境发出热能的特征,研究相变材料在粮食仓储中的应用,减小外界环境对粮仓温度的影响,达到恒温绿色生态储粮的目的。     

储粮害虫磷化氢抗性分子遗传学研究进展

由于长期单一使用磷化氢,储粮害虫对其产生的抗药性日益增强,已成为威胁粮食安全储藏的重大问题。自从发现两个磷化氢抗性基因rph1和rph2,以及完成赤拟谷盗全基因测序以来,储粮害虫磷化氢抗性基因的相关研究迅速发展。近年来,在抗性基因的鉴定、表达、进化、突变等研究方面取得了一定成果,为储粮害虫磷化氢抗性治理提供了新的科学指导。本文就储粮害虫磷化氢抗性分子遗传学的研究进展进行综述。