多元多熟种植制度复种指数计算方法探讨

针对９０年代种植制度变革的新特点,分析了间套作、复种及复种指数的意义,讨论了区别间套作的共生期标准、作物标准熟期与熟数系数以及面积系数等概念,提出了多样化的多元多熟种植条件下复种指数的计算规则和方法。     

棉花纤维超分子结构参数的遗传分析

本研究利用X—射线衍射技术,对陆地棉(G.hirsutum L.)、海岛棉(G.barbadense L.)及其F_1、F_2杂种纤维超分子结构和纤维强度的分析表明:横向晶粒尺寸、结晶度和取向分散角a的分离范围较小,遗传方式简单,有显性或超显性效应;杂种F_2的螺旋角(?)分离范围极广,既有超高亲,也有超低亲变异,遗传方式复杂,既有显性效应,也有基因互作效应.陆地棉纤维强度的遗传改良应主要依赖于(?)角与取向分布角(?)的优化.棉纤维强度是重要原棉品质指标,其高低受多重因素的综合影响,其中成熟纤维的超分子结构是导致棉花种间、品种间纤维强度差异的主要原因.分析其遗传特性,对指导优质棉育种意义重大.     

柳绕地区混农林业立体经营模式与效益分析

在辽宁柳绕地区通过多年试验与生产实践表明，进行混农林业立体经营，以造林前１年或１年生林地间种西瓜，第２～５年生林地间种玉米，然后再间种几年紫花苜蓿，即林瓜－林粮－林草立体经营模式效果最佳。其主要优点是：提高光能利用率，为社会增加粮食和瓜果，为农民和林场增加收入，促进林木生长，提高森林生产力。本文提出了混农林业立体经营的最佳模式及取得最佳效益的关键技术，为平原林区进行混农林业立体经营提供了重要的科学依据     

竹伐桩内施化肥的研究

在竹伐桩内施化肥,竹子更易吸收,肥料既不会被雨水大量冲走,也不会被杂草吸收。与沟施与围施相比,竹伐桩内施肥具有节省劳力、防止水土流失等优点,同时能加速伐桩腐烂又不伤鞭。利用竹桩伐施碳酸氢铵可以提高出笋率和竹材产量,其肥效与开沟施等氮量尿素基本相同。由于碳酸氢铵肥效低且容易引起竹鞭大量腐烂而不受人们欢迎,而伐桩内施碳酸氢铵可以克服上述缺点。所以,伐桩内施肥不仅为毛竹高产提供了施肥的新方法,而且为滞销的碳酸氢铵开辟了竹区这一新市场。     

GA_3及不同比例MS培养基对蕨菜孢子萌发的影响

采用300mg.L-1GA3及不同比例的MS培养基对当年和上一年采集的蕨菜孢子进行萌发试验。结果表明,GA3处理可以促进孢子提早萌发,并且可提高上一年孢子的萌发率,但对提高当年新采集的孢子萌发率作用不明显。全MS培养基对提高孢子萌发量效果最好。     

GA3及不同比例MS培养基对蕨菜孢子萌发的影响

采用300mg.L-1GA3及不同比例的MS培养基对当年和上一年采集的蕨菜孢子进行萌发试验。结果表明,GA3处理可以促进孢子提早萌发,并且可提高上一年孢子的萌发率,但对提高当年新采集的孢子萌发率作用不明显。全MS培养基对提高孢子萌发量效果最好。     

天台山云锦杜鹃的开花与结实特性

 对天台山云锦杜鹃3个种群的花芽发育、花部形态、花生命周期及结实状况等进行野外定位观测, 结果显示: 云锦杜鹃于5月初开花, 花期接近25 d, 花生命周期6 d左右, 其中黄山松林中的云锦杜鹃种群花生命周期最短, 平均为5.8 d, 主要原因是光照时间长, 湿度相对较低, 花形态较小。云锦杜鹃的结实率不高, 结籽率很低, 观云洞种群、黄经洞种群和永字亭种群的平均结籽率分别为35.05%、32.51%和31.93% , 且花生命周期与结实率及结籽率呈显著负相关。另外, 由于光照和湿度等环境因素的差异, 种群间的结籽率也有显著差异。     

Seasonal variations in the crop contents of scavenging Helmeted Guinea Fowls (Numida meleagris,L.) in Parakou (Benin)

1. An experiment was carried out with 120 helmeted guinea fowls during one year in Parakou (Benin). Feed intake, ingredient and chemical composition, along with the nutritional adequacy of scavenging diets were measured during the rainy season (November–February) and dry season (March–October) in order to propose supplementation strategies. Ingredients found in crops were identified and allocated into 6 main categories (supplemental feed, seeds, green forages, animal materials, mineral matter and unidentified materials).

2. Mean dry weights of crop contents were significantly higher in the rainy than in the dry season. Amounts and proportions of supplemental feed and seeds were not significantly different between seasons, whereas those of green forage, animal materials and mineral matter were higher in rainy season. Supplemental feed, especially maize and sorghum, was the largest component of the crop content in both seasons. The most represented grass seeds were Panicum maximum (rainy season) and Rottboellia cochinchinensis (dry season).

3. Dietary concentrations of organic matter, non-nitrogen extract and metabolisable energy were higher in the dry season, while mineral concentrations were higher in the rainy season. There were no significant differences between the two seasons in dry matter, crude protein or crude fibre.

4. Scavenging provided insufficient nutrients and energy to allow guinea fowls to be productive. Therefore, more nutritionally balanced supplementary feed would be required during both seasons.     

The nutritive value of cassava starch extraction residue for growing ducks

The cassava root meal (CRM) has been utilized as a cheap energy alternative to replace maize in poultry diets. Recently, the CRM in turn has an increasing demand for starch extraction industry, which renders large amounts of residues. This study evaluated the nutrient composition, amino acid profile, and feeding value of cassava starch extraction residue meal (CReM) for growing ducks. A total of 960, 11-day-old, ducklings were housed in 24 floor pens and allocated randomly into four dietary treatments: (i) 0CReM (control), (ii) 50 g CReM/kg, (iii) 100 g CReM/kg, and (iv) 150 g CReM/kg. The analyses (/kg) of CReM showed high gross energy (3306.88 kcal), ME (2109.54 kcal), and starch (514.0 g), with poor crude protein (20.9 g) and moderate crude fiber (140.0 g) and ash (60.0 g) contents. The total amino acid (AA) content amounted to 19.9 g/kg of CReM DM, in which the methionine, lysine, cystine, and isoleucine were present in low levels. The dietary inclusion of CReM up to 150 g/kg, between 11 and 42 days of age, had no significant effects (P?>?0.05) on duck growth parameters, mortality, dressed weight, internal organs, or abdominal fat. Besides, the tested CReM levels did not show any significant effect on the blood proteins or liver enzymes. The results, therefore, revealed that the CReM contains a considerable amount of energy and could be incorporated successfully up to 150 g/kg in the diets of growing ducks.     

Microencapsulation of clove essential oil improves its antifungal activity against Penicillium digitatum in vitro and green mould on Navel oranges

?Relatively high levels of clove essential oil (CEO) necessary for in vivo inhibition of postharvest pathogens imply that its antifungal activity should be reinforced. Hence, this study aimed to determine whether microencapsulation technology enhances the antifungal activity of CEO against Penicillium digitatum, the causal agent of citrus green mould, in vitro and on Navel oranges. Microencapsulation of CEO resulted in a respective reduction of minimum inhibitory concentration and minimum fungicidal concentration from 500 μg/ml to 125 μg/ml and 250 μg/ml, indicating the enhancement of fungistatic and fungicidal activity with respect to that of the pure oil. CEO microcapsules had the best control of lesion diameter and decay development (0.79 mm, 8.64%) in Navel oranges after 5 days’ storage at 25°C, followed by pure oil treatment (4.2 mm, 55.56%). In the vapour phase, CEO microcapsules also exhibited the highest ability to control green mould of Navel oranges. Furthermore, CEO microcapsules showed stronger suppressive activity of spore germination and germ tube elongation of P. digitatum than pure oil. These results indicate that the antifungal activity of CEO was considerably enhanced when it was converted into a microcapsule.