硝酸稀土在豆科牧草生产中应用的研究

采用不同浓度的硝酸稀土材料,对紫花苜蓿、白三叶、红豆草三种优良牧草进行了为期３年的生产应用性研究,结果表明：６００ｍｇ／ｋｇ～６５０ｍｇ／ｋｇ稀土浓度能够显著地提高豆科牧草产草量和饲料的品质,促进豆科牧草的根瘤发育,稀土主要在牧草的营养生长埋藏起作用。     

Soil properties and plant production after short-term fallows in Senegal

Abstract. Field trials of vegetation modification were carried out to test the hypothesis that the management of key plant groups such as trees, perennial grasses and legumes would improve soil chemical properties in short-term fallows. Soil properties and plant production during a 4-year fallow period and millet yields after clearing were recorded at two sites representing dry and subhumid climates in Senegal, West Africa. During the four years of fallow, soil organic matter did not vary significantly at either site. A decrease in amounts of Olsen P, calcium and potassium in soil (0–10 cm depth) by 42–50% occurred at one site due to an effect of perennial grasses. The highest millet yields were measured in plots on which the largest amounts of biomass had been burnt after clear-cutting. These results confirmed that short-term fallows do not replenish soil organic matter and nutrient contents. The introduction of planted species did not arrest the decline in soil quality.     

Variation in temperature requirements for germination and early seedling root development in Chamaecrista rotundifolia and three allied species

Two experiments are discussed. In the first, rates of root elongation during the first four days of growth at 25 °C were studied in Chamaecrista rotundifolia (34 accessions), C. nictitans (2 accessions), C. pilosa (1 accession) and C. serpens (3 accessions). In the second, a comparison was made of germination characteristics of 14 accessions of C. rotundifolia and one of C. pilosa at nine constant temperatures (11–27 °C). Entries included accessions from a wide latitudinal range. There were statistically significant differences in root length on all four days of measurement. No accession had significantly longer roots than the commercial cultivar cv. Wynn on day 1, but over the following three days, 4, 10 and 13 accessions had significantly longer roots, respectively. Root length on day 4 was positively correlated with latitude of origin. In the second experiment, maximum germination occurred at 25.5–27 °C, with progressively lower percentages at lower temperatures. There were highly significant differences between accessions at each temperature (P<0.001), and a highly significant accession × temperature interaction. No accession had a higher germination percentage than cv. Wynn at any temperature. Percentage mortality differed significantly (P<0.05) at all temperatures except 27 °C. Mortality at low temperature was negatively correlated with latitude of provenance. Increased temperatures up to 22.5 °C reduced the time taken to reach 50% of maximum germination (T₅₀), and thereafter it was reasonably constant. With one exception (22.5 °C), no accession germinated significantly more quickly than cv. Wynn, and at 13 °C cv. Wynn germinated significantly more rapidly than all other entries. Over all temperatures, there was a significant negative correlation between days to 50% germination and latitude of provenance. Estimated base temperature for germination (T _b ) ranged from 10.6 °C to 13.6 °C. T _b was positively correlated with latitude of provenance. It is argued that accessions from higher latitudes have developed mechanisms for survival of soft seed at low temperatures, low base germination temperature, germination rates and root elongation rates that adapt them to an environment with summer-dominant rainfall and winters which are too cool to support growth.     

芍药等8种植物COMT基因的生物信息学分析

植物咖啡酸-O-甲基转移酶(caffeic acid O-methyltransferase,COMT)基因对木质素的合成具有重要的调控作用。本研究采用生物信息学方法对芍药等8种植物COMT基因编码的氨基酸序列进行比对,进而对其蛋白理化性质、信号肽、跨膜结构域、磷酸化位点、亚细胞定位、二级结构与三级结构进行了预测与分析。结果表明,芍药等8种植物COMT基因编码氨基酸的一致性可达65.91%,平均相对分子量为39437.79 Da,带有酸性等电点,含量最丰富的氨基酸为亮氨酸(Leu)和丙氨酸(Ala),无信号肽,无跨膜结构域,磷酸化位点数量最多的为丝氨酸和苏氨酸,定位于细胞骨架和细胞质中可能性最大,二级结构则以α-螺旋和无规则卷曲为主,三维结构具有一定的相似性。这一结果为今后深入开展植物COMT基因功能研究提供了科学依据。     

《初学记》草部资料探微

《初学记》草部记录了粮食作物、花卉的相关资料,征引资料陂丰,征引典籍以经部、集部为主。草部资料的编纂具有内在逻辑性,3种体例之间具有前后照应性。草部具有较高的史料价值,从中也可看出一点唐代的时代特征。     

木质部溶质分析法测量豆科植物的生物固氮

固氮植物与未长根瘤的豆科植物所同化氮素的运输形式有所不同,许多豆科植物所固定氮素是以酰脲或酰胺的形式在木质部中运输的。测定一些豆科植物木质部液汁中酰脲的相对含量,则可以估测出该植物的固氮能力。该法县有取样方便、测量简单,对某些植物可以做到非破坏性测量等优点。     

牡丹·芍药应用基础研究现状及展望

综述了有关牡丹、芍药研究的发展现状,并针对洛阳牡丹产业化发展存在的问题,提出了积极的对策。     

Amelioration of a degraded Oxic Paleustalf by leguminous and natural fallows

Abstract. The restorative ability of herbaceous ( Psophocarpus palustris, Pueraria phaseoloides ) and woody ( Leucaena leucocephala, Senna siamea, Acacia leptocarpa, Acacia auriculiformis ) legume species and of natural regrowth was studied on an eroded and compacted Oxic Paleustalf in southwestern Nigeria. Compared to the control treatment that was continuously cropped for 15 years, four years of fallowing significantly improved test crop yields. However, fallowing with the above species did not substantially improve soil properties, particularly soil bulk density. A longer fallow period may be needed to amend soil physical conditions of this degraded Alfisol. Soil chemical properties were greatly improved following land clearing and plant biomass burning in 1993. However, the residual effect of burning on soil fertility was insignificant in the second cropping year. Among the fallow species, P. palustris and natural fallow showed the best residual effect on test crop performance. Despite the high biomass and nutrient yields of S. siamea and A. auriculiformis , test crop yields on these plots were low due to the border effects from the uncleared and fallowed subplots.     

甘肃省白龙江流域豆科植物根瘤菌共生固氮研究

对甘肃省白龙江流域甘南、陇南的大部分地区豆科植物——根瘤菌资源进行了调查 ,共采集 2 1属45种豆科植物 6 9份根瘤样品。从 6 9份样品中获 6 3株根瘤菌 ,对其中 44株根瘤以 13种寄主进行了回接试验 ,31株结瘤 ,结瘤率 70 .5 %。该区根瘤一般带有粉红色 ,形态比较规则。乙炔还原活力测定结果表明 ,88.5 %为有效根瘤。不同种根瘤固氮活性相差不大 ,但高于甘肃省其它地区。对豆科植物在蓄水保土 ,改良土壤状况中的地位进行了讨论。