菵草属、看麦娘属、梯牧草属部分植物颖果微形态研究

菵草属、看麦娘属和梯牧草属都属于禾本科早熟禾亚科,对中国产菵草属、看麦娘属和梯牧草属共6种植物的颖果微形态特征进行研究,以明确颖果微形态对于3个属的分类学意义。颖果在离子溅射仪中真空喷金后,在扫描电镜下观察和研究6种植物的颖果微形态特征。结果显示:(1)看麦娘、菵草属和梯牧草属颖果微形态特征为体长1～2 mm左右,颖果形状为卵圆形或梭形,背腹压扁或不明显,腹面凸起或凹起,种脐形状为圆形或披针形延伸到线状,颖果纹饰是条状或网状。(2)应用PAUP软件进行了3个属颖果性状的UPGMA聚类分析,在分支树上,菵草属和看麦娘属列为一个分支,梯牧草属单列另一支,颖果微形态的研究说明菵草属和看麦娘属有更近的亲缘关系。     

气候变化背景下江南地区人体舒适度时空分布特征

为定量评价江南地区人体舒适度时空演变特征,本研究基于江南地区1961—2011年434个常规气象观测站逐日相对湿度、平均气温资料,利用人体舒适度指数模型系统分析了江南地区人体舒适度季节变化及空间分布特征,并进行相应的风险区划。结果表明:(1)除夏季外,江南地区全年及各季节人体舒适度值空间分布由南向北呈现逐渐减小的带状分布。(2)研究发现江南地区舒适日、不舒适日由南到北逐渐减少,极不舒适日呈现明显相反的趋势。(3)江南地区全年及各季节人体舒适度值分别以0.302/10 a、0.162/10 a、0.211/10 a、0.355/10 a、0.484/10 a上升,全年及春、秋、冬舒适感逐渐增加,而夏季舒适感显著下降。(4)全年及春、秋、冬人体舒适度值均具有明显的突变特征,突变点约在20世纪80年代末,后期总体上表现为上升趋势,气候变化在一定程度上有利于全年及春、秋、冬舒适度增加,减少了夏季人体舒适感。该研究结果可为江南地区人居环境决策、旅游气候资源综合开发利用及旅游气象服务保障提供科学的依据。     

菵草属及其近缘属叶下表皮微形态的研究

为了探讨菵草属的系统学位置,采用次氯酸钠离析法制作叶表皮装片,用光学显微镜对菵草属及其近缘属植物的叶下表皮微形态特征进行观察。结果显示:菵草属及其近缘属,燕麦族和早熟禾族植物的叶下表皮均为典型的狐茅型,具有较高的一致性。脉间长细胞大多为长筒形,细胞壁大多平直,少数波状弯曲;脉间区短细胞稀少或常见;脉上都分布有刺细胞或短细胞;气孔器大多为2~3列;副卫细胞为平行形,少数为低圆屋顶形。叶表皮微形态显示菵草属不应划入虎尾草族,早熟禾族和燕麦族没有明显的界限,支持早熟禾族和燕麦族合并为广义的早熟禾族,菵草属归为广义的早熟禾族。     

基于颖果微形态特征探讨异颖草属的系统位置

为探讨异颖草属颖果微形态特征的分类学意义,利用体视显微镜和扫描电子显微镜对异颖草属及近缘属8种植物的颖果微形态进行了观察.结果显示,异颖草属颖果长椭圆形,稍背腹压扁,腹面凹,具沟,种脐披针形至缝状,胚比1/4左右,纹饰为条纹状.颖果微形态特征为异颖草属系统位置的确定提供了一定的依据,支持将异颖草属置于野青茅属.     

淫羊藿属植物杂交F1代植株形态和种间系统演化研究

淫羊藿属植物多数种类在形态分类性状上存在连续过渡的形态变异现象,导致种间的鉴别困难.本研究对粗毛淫羊藿、巫山淫羊藿、天平淫羊藿,3个物种合计29个居群之间的种间杂交F1代植株及其亲本形态学进行了比较研究.结果表明:AC×MY、AC×WU、WU×MY 3种组合杂交F1代的叶片形状表现为双亲过渡形态,控制淫羊藿花瓣距短于内萼片的基因可能是部分显性,E.acuminatum的花瓣和内萼片颜色属于显性遗传.所得结果为淫羊藿属植物分类学、种间系统关系及其起源与进化研究提供了新的资料和线索.     

ETH、KT和6-BA对绿豆幼苗形态建成和生化成分的效应研究

采用人工气候箱技术,研究ETH、KT、6-BA及ETH-KT、ETH—6-BA复配处理对绿豆幼苗形态、生化成分、内源激素及下胚轴细胞组织结构的调节效应,为绿豆芽菜的安全生产提供理论和技术支持。结果显示：与对照相比,处理组均可使绿豆幼苗下胚轴缩短和增粗、主根长缩短、侧根数减少（P<0.05）,其调节效应大小为ETH—6-BA>ETH-KT>ETH>6-BA>KT;ETH—6-BA可使下胚轴缩短35.78 %,增粗26.51 %,主根缩短65.43 %,并完全抑制侧根的产生。不同处理对绿豆幼苗的生化成分的效应大小存在差异（P<0.05）,ETH可使绿豆幼苗可溶性蛋白、可溶性糖和维生素C含量分别增加25.1 %、66.07 %和163.9 %;各处理调节效应的大小依次为ETH>ETH-KT>ETH—6-BA。各处理均在一定程度上改变了绿豆幼苗的内源激素含量,6-BA及ETH-6-BA可使IAA含量分别降低88.9%和33.3%,使ZR含量分别降低35.3% 和22.8%, ETH-6-BA 处理可使ABA 含量增加 156.9%。对绿豆幼苗下胚轴的增粗作用,ETH增加了髓内细胞数目和单个皮层细胞面积,减少了皮层细胞数,表现为髓和形成层面积的增大;6-BA与ETH—6-BA增加了髓和皮层的单个细胞面积,同时增大了髓、形成层和皮层的面积。     

栽培大麦（Hordeum vulgare L.）与纤毛鹅观草（Roegneria ciliaris (Trin) Nevski）属间杂种F1、F2和BC1的形态和细胞学研究

采用幼胚培养技术,获得了栽培大麦纤毛鹅观草之间的属间杂种。研究了杂种F1,F2和BC1的形态和细胞学特点。结果表明：杂种形态介于双亲之间,不同生育阶段其主要特征分别倾向双亲之一。在结实率和主要经济性状上F2和BC1较F1有相当大的提高,但生育期进展不大。根尖染色体计数和花粉母细胞减数分裂构型分析表明：F1、F2和BC1     

Cytogenetical and related studies in the genus Phleum L.

Phleum pratense L., the only species of Phleum that is of economic importance, is found in all temperate regions of the world.Cytogenetic evidence, in some cases, indicates the autopolyploid nature of P. pratense.Several anomalous cytological behaviors such as heavy walled coenocytes, neocentric chromosomes, uncoiled chromosomes, "cross-bridges" at second division, "globular" bodies, and B-chromosomes have been reported in timothy. Some of these behaviors appear to be related to sterility.Genetic work involving a study of chlorophyll deficiencies suggests hexasomic and tetradisomic modes of inheritance.Relationships among height, vigor, and fertility following cross- and self-pollination are discussed.Published with the approval of the Director of the West Virginia Agricultural Experiment Station as Scientific Paper No. 931.Associate Professor of Genetics, Agronomy and Genetics Department, West Virginia University, Morgantown, West Virginia, U.S.A.     

糯玉米颖果的发育及营养品质分析

为明确糯玉米颖果的发育规律,采用常规测定方法研究了糯玉米颖果的鲜重、干重变化及其淀粉、蛋白质、可溶性糖、脂肪的积累动态,借助扫描电镜观察了淀粉粒的发育。鲜食糯玉米最适宜的采收期为授粉后25~30 d;颖果中的淀粉含量前期增加较快,授粉20 d后增加缓慢;蛋白质含量先急剧降低后缓慢增加;可溶性糖含量先升高后降低;脂肪含量总体上呈上升趋势。籽粒鲜重与淀粉含量和蛋白质含量分别呈极显著正相关（r=0.915**）和负相关（r=-0.961**）,淀粉含量与蛋白质含量呈极显著负相关（r=-0.985**）。角质胚乳淀粉粒排列紧密,积压呈“足球状”;粉质胚乳淀粉粒排列疏松,呈多面体状。     

AlomySys: Modelling black-grass (Alopecurus myosuroides Huds.) germination and emergence,in interaction with seed characteristics,tillage and soil climate: II. Evaluation

Weed emergence models are increasingly necessary to evaluate and design cropping systems. The model AlomySys was developed for a frequent and harmful weed, i.e. Alopecurus myosuroides Huds. [Colbach, N., Dürr, C., Roger-Estrade, J., Caneill, J., 2005a. How to model the effects of farming practices on weed emergence. Weed Res. 45, 2–17; Colbach, N., Dürr, C., Roger-Estrade, J., Chauvel, B., Caneill, J., 2005b. AlomySys: modelling blackgrass (Alopecurus myosuroides Huds.) germination and emergence, in interaction with seed characteristics, tillage and soil climate. I. Construction. Eur. J. Agronomy] and is based on sub-models predicting (a) soil environment (climate, structure) resulting from the cropping system and external climate, (b) vertical soil seed distribution after tillage, and (c) seed survival, dormancy, germination and pre-emergent growth depending on soil environment, seed depth, characteristics and past history. In the present paper, the model was evaluated by comparing its simulated output to independent field observations, as a function of sowing/tillage date, seed depth, seed history and characteristics, soil climate and soil structure. The evaluation showed that the survival of the seed bank in top layers was systematically overestimated. In addition, some minor aspects were identified for future improvements, such as the pre-emergent seedling mortality in very compacted soil structures or germination rates of seeds that had not been previously stimulated by light. Despite these few shortcomings, the model simulates the timing and relative importance of the emergence flushes very well; in addition, the actual emerged seedling densities are usually predicted satisfactorily. Consequently, the model can be used to simulate the effects of cropping systems on black-grass emergence.     

AlomySys: Modelling black-grass (Alopecurus myosuroides Huds.) germination and emergence,in interaction with seed characteristics,tillage and soil climate: I. Construction

Models quantifying the effects of agricultural practices on weed emergence, in interaction with the soil, are necessary to evaluate and design cropping systems. In the present study, such a model was developed for black-grass (Alopecurus myosuroides Huds.), a harmful weed frequently found in rotations consisting mostly of winter crops. The model AlomySys was based on sub-models predicting (a) soil environment (climate, structure) resulting from the cropping system and weather, (b) vertical soil seed distribution after tillage, depending on the tool, the characteristics of the tillage implement and the soil structure; and (c) seed mortality, dormancy, germination and pre-emergent growth depending on soil environment, seed depth, characteristics and past history. Seed movements during tillage depend on the tool used, its characteristics, soil structure and on the initial position of the seed. Seed mortality increases with seed age; seed dormancy depends on seed age, seed depth, the conditions in which the seeds were produced and the past moisture and dryness conditions undergone by the seeds; germination is triggered by rain or tillage and driven by hydro-thermal time; pre-emergent shoot elongation depends on seed weight, on the conditions in which the seeds were produced and increases with thermal time; pre-emergent seedling mortality increases with soil dryness, clod size and seed depth. The sub-models were based either on existing models, or developed with literature data or additional experiments. Simulations were carried out to show how weed emergence can be reduced by adapting tillage mode and date to previous crop history.     

The cytological expression and inheritance of desynapsis in a clone of diploid timothy (Phleum nodosum L.)

Summary Cytological and inheritance studies were carried out on a desynaptic clone of Phleum nodosum L. (2n=14). The clone was completely male sterile in addition to showing a medium strong degree of desynapsis. Meiotic configurations and the frequencies of various abnormalities were recorded. A significant variation in the number of bivalents at metaphase I was attributed, at least in part, to environmental factors. Cytological study of the bivalents at metaphase I in the progeny from three crosses onto the desynaptic clone revealed a close fit to a 1:1 segregation for desynaptic versus non-desynaptic plants, indicating inheritance may be controlled by a single dominant gene. The absence of male fertility in non-desynaptic plants and the observation in anther cross-sections of delayed tapetal degeneration indicated that a male sterility mechanism was also likely present in this clone.     

小麦颖果腹部维管束韧皮部细胞的超微结构与功能分析

利用透射电镜技术,对小麦颖果发育过程中韧皮部细胞的超微结构进行了观察和分析。结果表明,在颖果发育的早期和中期,韧皮薄壁细胞与伴胞、中间细胞间,以及韧皮薄壁细胞之间都有丰富的胞间连丝。筛分子（SE）与伴胞（CC）间、SE/CC复合物之间、筛分子与韧皮薄壁细胞间缺少胞间连丝。但SE和CC与中间细胞间、以及中间细胞相     

施氮处理对水稻颖果淀粉积累和相关酶活性的影响

以扬稻6号和粳稻941为材料,通过盆栽试验,研究了不同施氮处理对水稻颖果淀粉积累和相关酶活性的影响。结果表明,增加穗肥施氮量显著降低颖果中的可溶性糖含量,淀粉含量有降低的趋势,但不明显。颖果中直链淀粉和支链淀粉含量随粒重的增加而上升,二者积累具有同步性;增加穗肥施氮量能显著降低颖果中直链淀粉含量,并使颖果中直链/总淀粉的比例降低,其效果要好于分蘖期施氮。分蘖期或孕穗期增施氮肥可以显著提高灌浆中、后期颖果中的ADPG焦磷酸化酶(AGP)、可溶性淀粉合酶(SSS)和淀粉分支酶(SBE)的活性,降低颖果中淀粉粒结合型淀粉合酶(GBSS)的活性。就施氮时期来看,孕穗期施氮(LH)对这些酶的促进或抑制效果好于分蘖期施氮(HL)。     

Wx蛋白缺失对水稻颖果和剑叶生理活性的影响

以转反义Wx基因粳稻和籼稻为材料的研究结果表明，直链淀粉含量降低后的转基因水稻颖果的光合和呼吸活性在发育前期显著高于亲本，但下降较快，到了发育中期(花后15~18 d)以后，就低于同期的亲本。但其SOD和CAT活性比其亲本下降得慢，从花后9 d开始一直保持着比亲本高的水平。花后转基因水稻剑叶的叶绿素含量、光合速率和SOD     

Impact of waterlogging and temperature on autumn growth,hardening and freezing tolerance of timothy (Phleum pratense)

Precipitation has generally increased in Norway during the last century, and climate projections indicate a further increase. The growing season has also become longer with higher temperatures, particularly in autumn. Previous studies have shown negative effects of high temperatures and, depending upon temperature conditions, contrasting effects of waterlogging on hardening capacity of timothy. We studied effects of waterlogging on seedlings of timothy (Phleum pratense, cv. Noreng) under three pre-acclimation temperatures: 3°C, 7°C, 12°C, and in autumn natural light in a phytotron at Holt, Tromsø (69°N). After temperature treatments, all plants were cold acclimated at 2°C for three weeks under continued waterlogging treatments. Freezing tolerance was determined by intact plants being frozen in pots at incremental temperature decreases in a programmable freezer. Waterlogging resulted in a higher probability of death after freezing, and a significantly reduced regrowth after three weeks at 18°C, 24 hrs light in a greenhouse. Increasing pre-acclimation temperatures also had a clear negative effect on freezing tolerance, but there was no interaction between temperatures and waterlogging. The results indicate that waterlogging may have negative implications for hardening of timothy and may contribute to reduced winter survival under the projected increase in autumn temperatures and precipitation.