干旱和CO_2浓度升高对干旱区春小麦气孔密度及分布的影响

通过对不同土壤水分状况、不同 CO2 浓度条件下春小麦叶片气孔的观测结果表明 :干旱和 CO2 浓度升高不仅影响叶片气孔密度 ,而且也影响其分布。随干旱程度的加剧 ,气孔密度有明显的上升趋势 ,气孔在叶片上的分布趋向均匀 ;随 CO2 浓度的升高 ,气孔密度有明显的下降趋势 ,其分布也趋向均匀。水分状况和 CO2 浓度相同时 ,气孔密度及分布受不同温度的影响     

ON THE STEM APEX,LEAF INITIATION AND EARLY LEAF ONTOGENY IN FILICALEAN FERNS

A general account of the stem apex organization in ferns is presented in support of the classical single apical cell concept. The range in variation of apical cells and of their modes of division are described. Evidence is brought out to indicate probable directing effects of the apical cell on modes of division of surrounding cells and on the leaf mother cell. Initiation of and eventual establishment of a stabilized apex in fern leaves is described. Of the more than 50 genera studied, the leaves of all are traceable to a single mother cell from which the leaf apical cell is cut out. Apical dichotomies are described in a number of genera as well as their effect on early leaf development. Results are discussed in a phylogenetic and morphogenetic context of leaf appendicularization.     

干旱和CO2浓度升高对干旱区春小麦气孔密度及分布的影响

 通过对不同土壤水分状况、不同CO2浓度条件下春小麦叶片气孔的观测结果表明：干旱和CO2浓度升高不仅影响叶片气孔密度,而且也影响其分布。随干旱程度的加剧,气孔密度有明显的上升趋势,气孔在叶片上的分布趋向均匀;随CO2浓度的升高,气孔密度有明显的下降趋势,其分布也趋向均匀。水分状况和CO2浓度相同时,气孔密度及分布受不同温度的影响。     

小麦叶片细胞周质微管的研究

采用铜网粘附-负染色法,并结合超薄切片,对小麦幼叶和成熟叶片细胞内的周质微管进行了研究,结果如下: (1) 粘附于铜网支持膜上的质膜片段,往往包含一个组织中心的微管体系。微管组织中心具有电子致密度很高的浓密物质。微管从组织中心呈辐射状或扇形分布。微管之间,有单个或数根成束排列, 有的相互平行,有的则相互交叉形成网状结构。微管的外径为24—24.76毫微米,最大长度为12微米。(2) 周质微管与质膜之间有密切联系,两者之间有连丝结构(“桥”)相连接。微管-桥-质膜三者结合形成一个稳定的体系。(3) 不仅质膜能粘附于铜网的福尔马支持膜上,分离原生质体残留的细胞壁纤维素微丝也能粘附于其上。被粘附的网状排列的纤维素微丝与幼叶细胞中周质微管的网状排列相一致,说明周质微管与纤维素微丝排列方向的密切关系。(4) 正在迅速生长的幼叶细胞比成熟叶片具有更多的周质微管和小泡结构(Vesicles),显示这两种细胞器的数量与细胞生长及细胞壁增生加厚的活动强度成正相关。     

普通小麦特殊染色体构型环状单价体和类等臂单价的研究

在植物花粉母细胞减数分裂中期Ⅰ出现的单价体,因不配对常呈捧状或弯曲成V形而独立于赤道板之外,然而有时其自身的两臀也会配对发生交叉而成环状,这种环状单价体在黑麦、大麦和小麦中已有报道。环状单价体的研究对染色体特异性配对等基本理论问题有重要的意义。1987和1988年,我们在鉴定(中国春单体×小偃6号)F_1单     

小麦叶片愈伤组织及其再生植株的诱导

小麦幼苗基部外植体在补加２,４－Ｄ的ＭＳ、Ｎ６、ＢＡ１（３）培养基上均可诱导出愈伤组织,２,４－Ｄ的最适浓度为２．０ｍｇ／Ｌ;愈伤组织的增殖速度与切段部位及基本培养基有关,其中在以ＭＳ补加２．０ｍｇ／Ｌ２,４－Ｄ的培养基上诱导出的愈伤组织增长速度最快;最后讨论了小麦愈伤组织幼苗诱导率低的原因及可能解决的方法。     

LEAF AND APICAL GROWTH CHARACTERISTICS IN TRITICUM

Leaf initiation rate, leaf primordium growth rates, and apical volume growth rates were determined for seedlings of Triticum aestivum cv. Ramona 50 under controlled environmental conditions. Three leaf primordia are present in the caryopsis, and three more leaves are initiated within the first two weeks after germination with a mean plastochron length of 95.5 hr. Volume growth rates of the apical region were determined on six apices which had six primordia each. The mean radial expansion rate was 0.467/plastochron, and the vertical expansion rate was 0.457/plastochron. The volume expansion rate was 1.393/plastochron. The mean volume doubling time was 0.498 plastochrons or 47.1 hr.     

小麦核仁在细胞周期中的变化

运用Bernhard染色方法研究了小麦根端分生组织细胞核仁在细胞周期中的变化。结果显示,间期核仁染色很深,能够区分出纤维中心（FC）、致密纤维组分（DFC）和颗粒组分（G）,而染色质被漂白,在染色质间可以观察到细小的RNP颗粒。进入前期,在染色质的边缘有小的RNP颗粒分布。中期,染色体周边分布着类似于间期核仁的深染的大RNP颗粒,形成一个不完全连续的“鞘”状结构;在染色体内部看不到类似核仁的深染颗粒。到了后期时,仍可见RNP“鞘”状结构的存在。进入末期,这些RNP植物逐渐由“鞘”脱离,最后参与新核仁的形成。这些结果表明,核仁解体后的物质直接转移到了中期染色的表面,并形成不连续的表层,没有进入染色体的内部。     

冬小麦低温春化过程中茎尖细胞超微结构的变化与玉米赤霉烯酮的关系

玉米赤霉烯酮(zearalenone, ZEN)是Stob等于1962年首先从玉米赤霉菌培养物中分离出的次生代谢产物,它具有动物雌性激素的作用,也能促进某些真菌形成子实体,被认为是真菌的一种性激素,80年代初发现亦存在于高等植物体内。多年的研究结果表明,ZEN与植物的许多发育过程,包括春化作用、光周期诱导以及授粉受精过程均有密切的关系,可能ZEN参与了小麦成花诱导过程的调控,但其调控机制不明。为进一步研究小麦春化过程中茎尖细胞超微结构的变化与ZEN的相关性,我们以春化过程中的冬小麦幼芽为材料,对茎尖细胞超微结构以及与之相应的ZEN含量变化进行了分析。     

12个不同基因型冬小麦的光合能力

 研究了12个不同基因型冬小麦(Triticum aestivum)品种(其中两个为北京本地品种)的光合能力。结果表明：小偃22、陕麦897和8907-11-5三个品种的净光合速率超过20μmolCO2·m-2·s-1,均比其它实验品种高,其PSⅡ总的光化学量子产额(Yield)、光化学荧光猝灭系数(qP)和水分利用效率(WUE)也较高;而其暗呼吸速率和非光化学荧光猝灭系数(qN)较低,表现出具有良好的光合生理功能,而且这些参数具有连锁相关的趋势。因此,北京地区要引种外地具有优良光合生理功能的冬小麦作为栽培品种或育种亲本时,在所实验的10个外地品种中,上述3个品种应为首选品种。     

小麦核仁的超微结构在细胞周期中的变化

应用整体银染技术在电镜下对小麦（Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ Ｌ．）根端分生细胞核仁在细胞周期中的超微结构变化进行了研究。结果显示,间期核仁染色很深,能够区分出纤维中心、密集纤维成分、颗粒成分和核仁液泡等结构;染色质上也布满大量染色浅的细小银粒。前期,随着核仁的解体和染色质的集缩,染色质的边缘逐渐出现深染的大颗粒;到前期末时,大量的核仁物质向染色体周围扩散并附着到其表面。中期染色体的周边分布着来自解体核仁的银染大颗粒,形成一个不大均匀也不完全连续的“鞘”状结构。后期仍可见这种“鞘”状结构的存在。进入末期,这些银染核仁物质逐渐由“鞘”脱离,彼此融合形成前核仁体,最后参与新核仁的形成。这些结果表明,核仁解体后的物质直接转移到了染色体的表面,并形成一个不连续的表层,没有进入染色体内部;染色体内部的银染颗粒与核仁及其解体物质无关     

HISTOGENESIS OF LEAF VENATION IN TRIFOLIUM WORMSKIOLDII (LEGUMINOSAE)

The histogenesis of the leaf venation in Trifolium wormskioldii was followed, using whole cleared leaflets and transverse and paradermal microtome sections. Mature leaflets are about 8 mm in length. The midvein precambium appears in leaflets 100 μ in length; secondary vein procambium is first seen in 230 μ leaflets; procambium of minor veins first appears in leaflets 400-600 μ in length. Phloem is apparent before xylem, in midvein, secondary veins, and minor veins. Vein endings are initiated and they mature last. No evidence was found to support the theory of “vein breakage.” In the greenhouse 24 days elapsed from leaf initiation to exposure of leaf tips; 6 more days elapsed until full leaf expansion.     

BASIDIOSPORE INITIATION AND EARLY DEVELOPMENT IN COPRINUS CINEREUS

Early basidiospore development in Coprinus cinereus has been divided into four stages: 1) inception, 2) asymmetric growth, 3) equal enlargement, 4) elongation, all based on changes in spore size and shape, wall layering, and cytoplasm. The hilar appendix body formed on the adaxial side of the stage 1 basidiospore, persisted through all stages studied, and predicted the site of the hilar appendix. The hilar appendix formed in stage 2 by modification of certain wall layers. A band of peripheral endoplasmic reticulum covered an average of 38 % of the lower spore wall in stage 3 and was oriented around the axis of growth. Stage 4 was initiated by a break in wall layer 3 at the spore apex and the disappearance of the peripheral endoplasmic reticulum. A pore cap formed on the spore apex during spore elongation. The spore wall consisted at first of three layers and became six layered by deposition of layers between two of the initial layers. Cytoplasmic changes associated with spore growth included presence of small vesicles at stage 1 and larger Golgi vesicles later, absence of mitochondria and probable Golgi cisternae from the spore until stage 3, and presence of a zone nearly free of ribosomes and organelles under the spore apex in stage 4. Functions of the hilar appendix body, peripheral endoplasmic reticulum and the different wall layers in control of spore shape are discussed.     

由小-簇麦杂种悬浮细胞和原生质体再生植株

１９８８年以来,小麦原生质体培养取得了重要进展［１—７］,但成功还仅限于少数基因型,因此,为了建立和不断完善小麦及其他禾谷类植物原生质体培养的技术体系,还有待在更多的基因型中进行探索。在小麦远缘杂种系统中,１９９０年王铁邦等［８］培养小－偃麦原生质体获得成功。本文报道由普通小麦－簇毛麦杂种悬浮细胞和原生质体再生植株的结果。材料和方法起始材料取自本实验室继代保存近２年的小－簇麦杂种（２ｎ＝４ｘ＝２８）愈伤组织。该愈伤组织是由小麦（ＴｒｉｔｉｃｕｍａｅｓｔｉｖｕｍＬ．,品种：“农大１４６”）×簇毛麦…     

LEAF INITIATION RATES AND VOLUME GROWTH RATES IN THE SHOOT APEX OF CHRYSANTHEMUM

The leaf initiation rate and apical volume growth rate of lateral shoots of Chrysanthemum morifolium ‘Improved Albatross III’ were determined for plants growing under controlled environment conditions. After removal of the terminal bud, the top two lateral buds produced leaves at a rate of 1.4 to 1.6 leaves/day for the first 9 or 10 days. At about the 10th day there appeared to be an abrupt shift to a lower initiation rate of 0.7 to 0.8 leaves/day. Defoliation by periodic removal of leaves larger than 1 cm caused a statistically significant increase in initiation rate, but not to as high a rate as that of the first 10 days of bud growth. Volume growth rates of the apical region were determined from transverse sections of five apices, according to the method of Richards (1951). The apical region was found to have a radial expansion rate of 0.1623/plastochron and a vertical expansion rate of 0.0494/plastochron. The volume growth rate was calculated to be 0.3740/plastochron and the volume doubling time to be 1.85 plastochrons or 56 to 63 hr.