五唇兰大孢子发生的超微结构观察

五唇兰(Doritis pulcherrima Lind l．)大孢子母细胞在减数分裂前呈长圆形,细胞核偏向珠孔端,细胞呈现极性分化。大孢子母细胞第一次减数分裂形成二分体。随后,二分体珠孔端的一个细胞退化,合点端的一个细胞体积增大成为功能大孢子。功能大孢子进行第二次减数分裂,形成二核胚囊。这一过程属于双孢子葱型胚囊的大孢子发生类型。珠孔端的二分体细胞(大孢子)在退化过程中质膜保持完好,液泡数量增多,染色质高度凝集,具有细胞程序死亡的部分特征。功能大孢子的细胞器和染色质分布均匀。功能大孢子合点端的细胞壁上有发达的胞间连丝,二核胚囊期胞间连丝消失。在功能大孢子靠近合点端一侧有吞噬结构,其内含有结构模糊的细胞器     

The effect of extended exposure to hypersaline conditions on the germination of five inland halophyte species

In order to determine how salinity and exposure time affect seed viability and germination, seeds of five halophytes, Atriplex prostrata, Hordeum jubatum, Salicornia europaea, Spergularia marina, and Suaeda calceoliformis were exposed to 3.0, 5.0, and 10.0% NaCl solutions for 30, 60, 90, 365, and 730 d. Recovery experiments in distilled water indicated significantly different species responses to salinity over time. Percentage germination and rate of germination in H. jubatum were dramatically reduced following extended exposure and all seeds exposed to 10% NaCl for > 1 yr failed to germinate. Spergularia marina seeds were stimulated following short-term exposure to 3% NaCl; however, germination was delayed and overall germination was significantly reduced with exposure time in the two higher salinity levels. Percentage germination in A. prostrata decreased over time, but salinity level was not related to this reduction. Germination of S. europaea and S. calceoliformis, the most salt-tolerant species being tested, was stimulated by exposure to high salinity. Both species had a significant increase in percentage germination and in the germination rate when compared to seeds germinated in distilled water. Baseline germination data from seeds placed in 0, 1, 2, and 3% NaCl solutions indicated that S. europaea and S. calceoliformis were the only species to germinate in the 3% NaCl solution. Spergularia marina failed to germinate in the 2% NaCl treatment, and germination of A. prostrata and H. jubatum was significantly reduced at this salinity level. It is concluded that prolonged exposure to saline solutions can inhibit or stimulate germination in certain species, and the resulting germination and recovery responses are related to the duration and intensity of their exposure to salt in their natural habitats.     

中国神农架蜡梅属一新变种和新变型

描述了蜡梅（Chimonanthus praecox L.）一新变种即卷瓣蜡梅,该变种与原变种的主要区别是中花被片高度反卷,中被片颜色为白色或金黄色,主要分布于神农架林区。其中中被片颜色为白色的卷瓣蜡梅可以被看作一个新变型跳枝蜡梅。     

促进铁皮石斛试管苗移栽成活的研究

目的有效加速铁皮石斛试管苗的人工繁殖.方法:对铁皮石斛试管苗在移植时期进行不同基质(有无伴生植被)、根长和营养液浓度等方面的研究.结果:最适宜的基质是1/3泥炭 1/3锯末 1/3珍珠岩,覆以苔藓类伴生植被可大大提高移栽成活率.组培苗根长在0.5～1.0 cm时是移植的最佳时期,移植半个月后施放1/2倍营养液为最好.结论:对铁皮石斛中药的GAP种植具有重要的指导意义.     

Agricultural production of halophytes irrigated with seawater

Summary Growing agricultural crops with direct seawater irrigation has progressed within the past few years from the conceptual to the experimental phase. This has been accomplished by selecting halophytes with inherently high salinity tolerance for use as crop plants rather than by increasing the ability of traditional crop plants to tolerate seawater. Some of the halophytes being investigated for use as crops in seawater irrigation scenarios have high nutritional value as forage or fodder crops. Most of them also have high digestibility. The limiting factor in such use is their high salt content, but this limitation can be moderated. However, since seeds of halophytes do not accumulate salt any more than do those of glycophytes, the greatest promise for seawater-irrigated halophytes probably will be as seed crops. The seeds of many halophytes have high protein and oil contents and compare favorably with traditional oilseed crops. Sustained high yields of seed and biomass already have been obtained from some halophytes irrigated with seawater, and within the next few years seawater agriculture should proceed from the experimental to the operational phase.     

Spatially explicit patterns in a dryland's soil respiration and relationships with climate,whole plant photosynthesis and soil fertility

Arid and semiarid ecosystems play a significant role in regulating global carbon cycling, yet our understanding of the controls over the dominant pathways of dryland CO₂ exchange remains poor. Substantial amounts of dryland soil are not covered by vascular plants and this patchiness in cover has important implications for spatial patterns and controls of carbon cycling. Spatial variation in soil respiration has been attributed to variation in soil moisture, temperature, nutrients and rhizodeposition, while seasonal patterns have been attributed to changes in moisture, temperature and photosynthetic inputs belowground. To characterize how controls over respiration vary spatially and temporally in a dryland ecosystem and to concurrently explore multiple potential controls, we estimated whole plant net photosynthesis (A_net) and soil respiration at four distances from the plant base, as well as corresponding fine root biomass and soil carbon and nitrogen pools, four times during a growing season. To determine if the controls vary between different plant functional types for Colorado Plateau species, measurements were made on the C₄ shrub, Atriplex confertifolia, and C₃ grass, Achnatherum hymenoides. Soil respiration declined throughout the growing season and diminished with distance from the plant base, though variations in both were much smaller than expected. The strongest relationship was between soil respiration and soil moisture. Soil respiration was correlated with whole plant A_net, although the relationship varied between species and distance from plant base. In the especially dry year of this study we did not observe any consistent correlations between soil respiration and soil carbon or nitrogen pools. Our findings suggest that abiotic factors, especially soil moisture, strongly regulate the response of soil respiration to biotic factors and soil carbon and nitrogen pools in dryland communities and, at least in dry years, may override expected spatial and seasonal patterns.     

猫叫综合征一家系高分辨染色体分析

本文采用高分辨染色体技术,对一例猫叫综合征患儿及其家系进行了分析,结 果提示,猫叫综合征染色体关键片段位于5p15.3→5pter。     

Halophytic crops for cultivation at seawater salinity

Summary Several hundred halophytes from salt marshes and salt deserts of the world have been evaluated in our laboratory at various degrees of intensity, and a few have been selected for development as crops. The development of the cultivars and the basic biology of the plants is being studied in Delaware in the United States. Agronomic testing, feeding trials, and development of the best agronomic practices are taking place in the saline desert at the American University in Cairo research station in Sadat City. Our present efforts focus primarily on three forages, one grain, and one vegetable.Sporobolus virginicus cultivars for both hay and pasture are being tested. ADistichlis spicata cultivar for hay has been identified, andSpartina patens is being evaluated as a hay as well. Although we do not yet have the data for a full year's growth in Egypt, forage yields of these various cultivars, when harvested as hay crops, range to 6.9 or more tons per acre, depending on the salinity and other environmental conditions, and the crude protein content as indicated by the nitrogen content ranges from 6 to 10%. Cultivars having the most useful agronomic qualities have been identified and are being increased in quantity. The grain cropKosteletzkya virginica is a perennial, producing a seed which resembles millet; its whole seeds contain approximately 25% protein and 15% oil. The yields of one of our better cultivars are about 1460 kg/ha (1300 lb/acre) when grown under 25 salinity. The vegetableAtriplex triangularis (similar to spinach) has been under mass selection for four years; a cultivar has been identified and seed is now being increased for this species.     

多叶斑叶兰繁殖体系建立及基于转录组的发育调控途径功能基因研究

多叶斑叶兰,是兰科斑叶兰属濒危野生植物、国家二级保护植物,具有极高的观赏和药用价值。多叶斑叶兰由于分布种群小,传播扩散能力弱,自然繁殖受到极大限制。以野生多叶斑叶兰茎段作为外植体,建立高效直接的植株再生体系。结合高通量转录组测序技术与生物信息学分析技术,深入挖掘参与多叶斑叶兰器官发育过程的功能基因。结果表明, Morel+2.0 mg/L 6-BA +0.5 mg/LKT+1.0 mg/LNAA+1g/L蛋白胨+25g/L 蔗糖+7.0 g/L Agar+1.0 g/L活性炭+30 g/L 香蕉+50 g/L土豆为最佳的芽诱导培养基;Morel+3 mg/L 6-BA+0.5mg/L NAA+0.5 mg/LKT+0.01 mg/L TDZ+2g/L蛋白胨+25g/L 蔗糖+7.0 g/L Agar+1.0 g/L活性炭30g/L 香蕉+50g/L 土豆为最佳芽增殖培养基;1/2 Morel+1.0 mg/L IBA+0.1 mg/L NAA+1 g/L+花宝2 号+25g/L 蔗糖+7.0g/L Agar +1.0 g/L活性炭+1g·L-1蛋白胨为最佳的生根培养基。转录组测序分析组装获得170688个Unigene,平均长度为584 bp, N50为833 bp。17352个Unigene比对注释到NR、Swiss-Prot、KOG、GO、KEGG数据库。野生苗与组培苗差异表达Unigene GO与KEGG功能富集分析显示, Unigene主要参与调控植物激素信号转导、植物形态发育、次生代谢过程以及能量代谢过程等生物学功能。进一步分析获得511个参与植物器官发育调控相关的转录因子。成功建立了多叶斑叶兰种质资源保存与高效离体再生体系,结合高通量转录组学技术,获得全面完整的多叶斑叶兰转录组信息特征,为后期多叶斑叶兰快速扩繁、遗传转化以及功能基因鉴定、遗传发育及其调控机制研究奠定基础。