玉米秸秆加鸡粪、酒糟发酵制作黄贮的研究

鸡粪与酒糟是廉价而来源广和非常规饲料,具有高活性及高蛋白的特点。用１０％,２０％,３０％的新鲜鸡粪、酒糟与玉米秸秆混合厌氧发酵１个月。分别测定了玉米黄贮饲料中的干物质,粗蛋白,中性洗涤纤维,ｐＨ值,氨态氮,有机酸变化及４８ｈ瘤胃干物质、粗蛋白、中性洗涤纤维降解率。结果表明,添加鸡粪能增加秸秆发酵的有机酸含量,降低ｐＨ值,并能提高秸秆的营养价值。加大鸡粪添加量能明显提高玉米黄贮瘤胃４８ｈ干物质、中性洗涤纤维降解率。添加酒糟能加速黄贮饲料ｐＨ值降低,增加玉米秸秆发酵的有机酸含量和乳酸、乙酸比例,酒糟对秸秆瘤胃降解率的提高效果不如鸡粪。     

应用分子标记检测水稻耐盐性的QTL

 利用特三矮2号/CB组合构建了重组自交系群体(RI)。以60个RFLP标记检测142个纯系的基因型。在含有NaCl的电导率为12 dS/m的培养液中鉴定这些纯系的耐盐性。结果表明,RI群体的耐盐性出现超亲分离。构建了一张覆盖11条染色体、含52个标记位点的连锁图。仅检测到一个位于第5染色体的位点(RG13)显著与耐盐性有连锁。该位点的表型贡献率为11.6%。来自母本的该位点可提高耐盐性。分别对RG13与其它59个标记位点间的互作做检测,仅发现3对互作显著,即RG13×RG104; RG13×RG143; RG13×RG716。当来自母本的RG13分别与来自父本的RG104和RG143重组时,均明显提高耐盐性。分别来自母本的RG13和RG716能产生提高耐盐性的互作。这些基因互作结果为超亲分离提供了理论依据。     

硒都黑猪体重与体尺指标的通径分析及最优回归模型的建立

为了探讨硒都黑猪体重与体尺指标的相关性,研究体尺指标对体重的直接和间接作用,构建体重与体尺的最优回归模型,试验选取190日龄硒都黑猪167头,测量体重(Y)与体高(X1)、体长(X2)、胸围(X3)、腹围(X4)、臀长(X5)、臀宽(X6)、臀围(X7)等各项体尺指标,并进行相关性分析、通径分析、逐步线性回归分析.结果...     

关于超级稻品种培育的资源和基因利用问题

 超级稻育种是矮化育种和杂种优势利用的深化,其本质是资源或基因及基因与环境互作的综合利用。为给超级稻育种提供思路,回顾和分析了超级稻育种中的资源及基因综合利用现状,包括籼粳基因渐渗及利用、栽培稻产量QTL累加及利用、野生稻产量及抗病基因发掘及利用、株型和根系相关基因的发掘及遗传改良等。指出由于真正能用于超级稻育种的有利基因及连锁标记还不多,水稻基因研究成果还不足以支撑超级稻分子育种,目前的超级稻育种仍以常规杂交技术和资源的综合利用为主。需要进一步发掘高产、优质、抗病虫、抗逆基因,常规育种技术与分子育种技术相结合,培育广适性或绿色超级稻。     

防腐浸渍处理后马铃薯癌肿病休眠孢子囊的大小变化

从采集的样本中发现马铃薯癌肿病的休眠孢子囊超过了已报道的形态大小,防腐浸渍液处理后休眠孢子囊平均大小缩小５０％以上。     

Soil microarthropod populations under natural and planted fallows in southwestern Nigeria

Microarthropods, such as soil mites (Acari) and springtails (Collembola), with body width between 0.08 mm and 0.5 mm play important roles in soil fertility maintenance through their regulatory activities in decomposition and nutrient turnover. Observations were made at IITA, Ibadan, southwestern Nigeria to evaluate the effects of natural regrowth of vegetation — mainly the shrub Chromolaena odorata — and three planted woody fallow species (Acacia leptocarpa, Senna siamea, and Leucaena leucocephala) on soil microarthropods in a degraded Alfisol. Populations of soil microarthropods were higher in the rainy season than the dry season, and populations were greater under natural fallow than for continuous cropping with maize (Zea mays) and cassava (Manihot esculenta). Populations of soil microarthropods were comparable under leucaena and natural fallow, but populations in the rainy season were 38% higher under senna than natural fallow and 36% higher under acacia than natural fallow. Regression analysis indicated that soil microarthropod population under fallow species was positively correlated with the lignin contents of leaf litter.This revised version was published online in November 2005 with corrections to the Cover Date.     

Soil fertility enhancement by planted tree-fallow species in the humid lowlands of Cameroon

Four shrub/tree species, Alchornea cordifolia, Pennisetum purpureum, Chromolaena odorata, and Calliandra calothyrsus were evaluated for their potential contribution to soil fertility restoration after two years fallow. Standing biomass, root distribution, nutrient content in the biomass, decomposition and nutrient release patterns, and association with mycorrhizae were the evaluation parameters. Alchornea and Pennisetum produced thehighest above-ground biomass, 66 t and 54 t/ha respectively. Pennisetum had more than 19 t/ha of root, 92% of which was in the 20 cm top soil. Alchornea had 74% of it roots in this soil layer, mostly as coarse roots while Calliandra had a deeper root system. Alchornea fallow accumulated more N and Ca, and Pennisetum fallow, more K than others, and mycorrhizae were mostly associated with Alchornea roots. The ranking of the different species for the decomposition rate was: Chromolaena > Pennisetum > Calliandra = Alchornea. Also release of nutrients during decomposition followed the order K > N > Ca. Alchornea and Pennisetum could be recommended as green manure species especially when high quantities of material are needed for weed or erosion control. Calliandra and Chromolaena, because of the flush of nutrient during early mass, loss can be used as mulch when the crop demand of nutrient is high. Alchornea decomposed slowly and therefore could be used to improve Chromolaena mulch, thus contributing to the build up of soil organic N and providing both short- and long-term nutrient release. This revised version was published online in June 2006 with corrections to the Cover Date.     

松香酸酯用于中性施胶的研究

合成了４种松香酯用于中性施胶。探讨了松香酯结构与施胶性能的关系,研究了施胶条件对香酯施胶效能的影响。松香酯在中,碱性条件下表现了优良的施胶效率。     

Seasonal shoot and needle growth of loblolly pine responds to thinning, fertilization, and crown position

The impacts of thinning, fertilization and crown position on seasonal growth of current-year shoots and foliage were studied in a 13-year-old loblolly pine (Pinus taeda L.) plantation in the sixth post-treatment year (1994). Length of new flushes, and their needle length, leaf area, and oven-dry weight were measured in the upper and lower crown from March through November. Total shoot length was the cumulative length of all flushes on a given shoot and total leaf area per shoot was the sum of leaf areas of the flushes.

By the end of June, first-flush foliage reached 70% of the November needle length (14.3 cm) and 65% of the final leaf area (15.0 cm²). Cumulative shoot length of first- and second-flush shoots achieved 95% of the annual length (30.3 cm), whereas total leaf area per shoot was 55% of the final value (75.3 dm²). Fertilization consistently stimulated fascicle needle length, dry weight, and leaf area in the upper crown. Mean leaf area of upper-crown shoots was increased by 64% six years after fertilization. A significant thinning effect was found to decrease mean leaf area per shoot in the crown. For most of the growing season, the thinned-fertilized trees produced substantially more leaf area per shoot throughout the crown than the thinned-nonfertilized trees. These thinned-fertilized trees also had greater needle length and dry weight, longer first flush shoots, and more leaf area per flush than trees in the thinned-nonfertilized plots. Needle length and leaf area of first flush shoots between April and July were linearly related to previous-month canopy air temperature (T_a). Total shoot length strongly depended on vertical light gradient (PPFD) within the canopy, whereas shoot leaf area was a function of both PPFD and T_a. Thus, trees produced larger and heavier fascicles, more and longer flush shoots, and more leaf area per shoot in the upper crown than the lower crown. We conclude that thinning, fertilization, and crown position regulate annual leaf area production of current-year shoots largely by affecting the expansion of first flush shoots and their foliage during the first half of the growing season.     

森林生态系统中凋落物的分解、积累与归还的模型计算

本文在森林生态系统生物量增长遵循Mitscherlich 模型的结果这一假定下,推导的模型对森林生态系统凋落物的年凋落量、年分解量及累积量进行了推算,并得到了很好的验证。该模型给出了林地凋落物贮量—年凋落量—年分解率三者是森林凋落物动态、养分循环的三要素的生物学意义,它们组成一个紧密联系的动态系统,若已知其中的任何二者,都可以推算出第三者。同时提出了用林地死根总量以及根系的分解速率来推算森林生态系统根系的年死量,为计算森林生态系统根系的生产力提供可靠方法。