Extirpation or Coexistence? Management of a Persistent Introduced Grass in a Prairie Restoration

Abstract Introduced perennial grasses are one of the greatest constraints to prairie restoration. Herbicides suppress but do not eliminate introduced grasses, so we explored the interaction of herbicide with two additional controls: heavy clipping (to simulate grazing) and competition from native species. A 50‐year‐old stand of the introduced perennial grass Agropyron cristatum (crested wheatgrass) in the northern Great Plains was seeded with native grasses and treated with herbicide annually for 7 years in a factorial experiment. Clipping was applied as a subplot treatment in the final 3 years. Both herbicide and clipping significantly reduced the cover of A. cristatum, but clipping produced an immediate and consistent decrease, whereas herbicide control varied among years. The cover of A. cristatum decreased significantly with increasing cover of a seeded native grass, Bouteloua gracilis (blue grama), suggesting that both top‐down (i.e., grazing) and bottom‐up (i.e., resource competition) strategies can contribute to A. cristatum control. No treatment had any effect on the seed bank of A. cristatum. Even in the most effective control treatments, A. cristatum persisted at low amounts (approximately 5% cover) throughout the experiment. The cover of B. gracilis increased significantly with seed addition and herbicide, and, after 7 years, was similar to that in undisturbed prairie. The total cover of native species increased significantly with clipping and herbicide, and species richness was significantly higher in plots receiving herbicide. Clipping season had no effect on any variable. In summary, no method extirpated A. cristatum, but clipping reduced its cover by 90% and doubled the cover of native species. Extirpation might not be a realistic goal, but relatively simple management allowed coexistence of native species.     

人工接种发酵茯砖茶降脂减肥作用研究

比较自然发酵与人工接种发酵茯砖茶对营养性肥胖大鼠的降脂减肥作用。结果表明与肥胖模型组比较,喂饲两类茯砖茶的大鼠体重、脂肪湿重、脂肪系数、甘油三酯（TG）、总胆固醇（TC）等指标均低于肥胖模型组,而高密度脂蛋白（HDL-C）则有明显提高。人工接种发酵茯砖茶与自然发酵茯砖茶均对营养性肥胖大鼠有降脂减肥作用,能显著改善大鼠的各项肥胖指标,人工接种发酵的茯砖茶在相关指标上均接近甚至优于自然发酵的茯砖茶。     

Effects of dew on eco-physiological traits and leaf structures of Leymus chinensis and Agropyron cristatum grown under drought stress

Aims To investigate the effects of dew on plants, we conducted the experiment to determine the physiological characteristics and leaf structures of Leymus chinensis and Agropyron cristatum in response to increasing dew under drought stress.Methods Four treatments (no dew, three times dew and five times dew per week under drought stress, and well-watering) were designed to examine leaf relative water content, water potential, net photosynthetic rate, water use efficiency, biomass, and leaf structures of L. chinensis and A. cristatum. Important findings There was a significant increase in the relative water content and water potential by simulated dew increase for two plants species under drought stress (p < 0.05). For A. cristatum, simulated dew increase significantly enhanced the net photosynthetic rate, stomatal conductance, and transpiration rate of plants under drought stress (p < 0.05). On the other hand, there was no significant difference in the stomatal conductance and transpiration rate for L. chinensis among treatments. Simulated dew increase improved the aboveground biomass and root biomass of two species. The ratio of yellow leaves to the total leaves was decreased by simulated dew increase for two species. Dew increase also protected leaf structures against the drought stress, suggesting that the dew increase can slow down the death process of leaves resulted from drought stress. Therefore, the study demonstrated that dew increased the available water for the leaves of L. chinensis and A. cristatum grown in the drought stress and thus had positive effects on the photosynthesis, water physiology and plant development.     

冠突散囊菌转录因子stf1基因的克隆及其表达分析

利用RACE技术获得了冠突散囊菌stf1基因的全长DNA序列。该序列全长3 029bp,开放阅读框长度为2 664bp,从114–2 908bp,在253bp处含有一个131bp的内含子,预测编码887个氨基酸。同源分析结果表明该基因与Snd1/p100转录因子同源。应用相对定量SYBR Green I荧光定量PCR技术对stf1基因在不同发育时期的表达量的差异进行了检测。结果表明,这个基因在子囊孢子时期的表达量最高,在分生孢子时期的表达量最低,相比子囊孢子时期下降了1倍。为深入研究冠突散囊菌的产孢调控机制奠定了一定的基础。     

普通小麦与冰草间杂种的细胞遗传学及其自交可育性

为了进一步研究冰草属（Ａｇｒｏｐｙｒｏｎ Ｇａｅｒｔｎ．）的Ｐ染色体组与小麦染色体组间的遗传关系和评价Ｐ染色体组在属间杂种自交可育性上的遗传效应,获得了普通小麦品种Ｆｕｋｕｈｏ（Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ ｃｖ．Ｆｕｋｕｈｏ,２ｎ＝４２;ＡＡＢＢＤＤ）与３个不同来源的四倍体冰草（Ａ．ｃｒｉｓｔａｔｕｍ＜Ｌ．＞Ｇａｅｒｔｎ．,２ｎ＝２８;ＰＰＰＰ）间的杂种（２ｎ＝３５;ＡＢＤＰＰ）。结果表明     

小麦-冰草衍生系3228主要产量性状的遗传分析

为了探讨小麦-冰草(Agropyron cristatum)衍生系3228的多粒(66～82粒/穗)特性在育种中的可利用性,本研究以3228与黄淮冬麦区5个主栽品种进行杂交,并将其杂种F_1分别种植于北京、陕西和四川,采用MINQUE(1)统计方法及AD模型对主要产量性状进行了遗传分析。在研究的6个产量性状中,均存在极显著的加性方差比率,普通广义遗传率在产量性状的遗传中所占比例较大,所有性状的遗传均存在加性和环境的互作。特别值得指出的是,3228在穗粒数方面具有极显著的加性和显性效应,在穗长、小穗数方面也具有极显著的加性效应,说明利用该种质对于提高小麦的穗粒数具有重要作用。     

湖南地区茯砖茶中金花菌的分离鉴定

对湖南地区茯砖茶上＂金花菌＂的菌落特征、形态特征进行了研究,并运用扫描电镜观察了其子囊孢子和分生孢子的发育过程,鉴定其为冠突散囊菌（Eurotium cristatum）。     

小麦-冰草多粒新种质的抗白粉病和高分子量麦谷蛋白亚基组成分析

穗粒数是决定小麦产量的三因素之一,因此通过远缘杂交创造多粒新种质,对于拓宽小麦育种的遗传基础和促进育种水平的持续提高具有重要意义。本研究以通过多年多点鉴定证明具有多粒特性(粒数/穗>80)的31份普通小麦-冰草(Agropyron cristatum,2n=4x=28,PPPP)衍生后代为材料,通过田间接种白粉病生理小种E09进行抗病性鉴定、采用SDS-PAGE方法进行高分子量麦谷蛋白亚基(HMW-GS)组成分析以及株高、有效分蘖等农艺性状调查,发现26份材料表现抗白粉病,12份材料具有优质高分子量麦谷蛋白亚基组合,亚基组成为(2*,7+8,5+10)或(1,7+8,5+10)。其中,8份材料的穗粒数大于80粒、株高小于75 cm、抗白粉病且具有优质高分子量麦谷蛋白亚基组合,这为未来培育兼具高产、优质、抗白粉病小麦新品种提供了重要的物质基础。此外,对多粒、抗白粉病和优质亚基的可能来源进行了讨论。     

通用线性模型筛选家禽生化多态遗传标记的探讨

本研究首次采用线性模型估计生化基因(表)型对产蛋量相关性状的效应,排除环境和遗传背景的差异,检测出效应显著的3种生化基因(表)型。Akp座位F型和Es-1座位AB型的开产蛋重显著降低, 效应的遗传本质有待于深入研究确认。 Tf位点对于36周龄体重的影响不属于基因多效或紧密连锁效应, 可能是距离较远基因连锁的结果,效应随基因间连锁与交换会在品系和世代间产生较大波动;或可能源于非控制误差。本研究还表明生化基因座位与数量性状基因位点(QTL)间的非紧密基因连锁可能大量存在, 但育种意义不大。 Abstract:The literature on associations between biochemical polymorphisms with a Mendelian basis and quantitative traitsis abundant,but it is often difficult to draw conclusions from results that vary in statistical significance and that are sometimes conflicting.Linear models were found capable in estimating associated effects of biochemical genes,precluding deviations due to environmental and population differences.Three biochemical gene- or phenotypes were detected to be significantly associated with laying-related traits.F of Akp locus and AB of Es-1 locus showed large associated effects on egg weight at onset of lay as the result of pleiotrophy or close linkage,or caused by heterogeneity,whereas association of BB at Tf locus with body weight at 36 weeks of age could be due to loose linkage or non-controlled errors which exhibited large variations between populations and possibly through generations Many biochemical loci were also revealed to be occasionally associated with laying-related traits,but few of them could be of breeding importance.