黄金树花器官发生及发育的形态解剖学研究

 利用普通光学显微镜和扫描电镜技术对黄金树花器官的发生及发育过程进行了观察。结果显示：（1）黄金树花器官的形态发生及发育过程集中于3月下旬～5月上旬进行,速度较快,历时较短。（2）花原基分化形成花的整个过程符合一般的分化顺序：花萼原基－花冠原基－雄蕊原基－雌蕊原基,且各原基在分化顺序上存在交叉。（3）花药及胚珠的发育与花器官的形态发生之间有明显的连续性,当花蕾直径为3.0 mm左右时花粉母细胞及完整的花粉囊壁形成,直径达到3.5 mm左右时胚珠中出现孢原细胞的分化,它直接起大孢子母细胞的功能。     

外源NO供体SNP浸种对盐胁迫下黄金树幼苗生长的影响

用不同浓度NO供体硝普钠(SNP)浸种黄金树种子得到其幼苗,采用NaCl琼脂法研究不同浓度盐胁迫对幼苗生长的影响.结果表明:50μmol/L SNP浸种可以明显缓解100 mmol/L NaCl胁迫对黄金树苗高生长造成的抑制作用,2 000μmol/L SNP浸种可以明显缓解100 mmol/L NaCl胁迫对黄金树发根数造成的抑制作用;黄金树种子在外源NO供体SNP浸种后萌发得到的幼苗耐盐性较优,可为黄金树耐盐种的选择提供参考.     

大岩桐组织培养研究进展

从大岩桐的再生途径、再生过程、培养基配方以及再生过程中出现的褐变、休眠、体细胞突变等对大岩桐组织培养的研究现状进行了回顾,并探讨了存在的主要问题及发展趋势,以期为今后的深入研究提供参考.     

Effect of wheat,legume and legume enriched wheat residue and nitrogen application on soil fertility under rice-wheat cropping system

The field experiments were conducted for two crop years of 1997?–?98 and 1998?–?99 at the Indian Agricultural Research Institute, New Delhi to study the effect of wheat, legume and legume enriched wheat residue (WR) on soil fertility under the rice-wheat cropping system. A rice-wheat cropping system without incorporation of residue depleted organic C over initial level by 0.061%, kjeldahl-N by 0.012%, available P by 0.7?kg ha^???1 and available K by 36?kg ha^???1, whereas incorporation of Sesbania green manure (SGM), mungbean residue (MBR), SGM?+?WR and MBR?+?WR increased organic C over the initial level by 0.071, 0.100, 0.163 and 0.133%, respectively, kjeldahl-N by 0.001, 0.004, 0.001 and 0.005% respectively, available P by 2.7, 5.0, 8.5 and 3.2?kg ha^???1, respectively and available K by 35, 5, 92 and 12?kg ha^???1, respectively in 2 years. As compared with no residue control, incorporation of WR increased organic C by 0.036?–?0.102%, kjeldahl-N by 0.002?–?0.007% and available K by 23?–?45?kg ha^?1, whereas incorporation of SGM and MBR increased organic C by 0.082?–?0.132 and 0.103?–?0.161%, respectively, kjeldahl-N by 0.009?–?0.023 and 0.005?–?0.013%, respectively and available K by 5?–?71 and 4?–?45?kg ha^???1, respectively. Incorporation of WR with SGM and MBR was more effective and increased organic C by 0.121?–?0.224 and 0.125?–?0.194%, respectively, kjeldahl-N by 0.005?–?0.029 and 0.010?–?0.021%, respectively and available K content by 23?–?128 and 11?–?116?kg ha^???1. Nitrogen application to rice also increased organic C, kjeldahl-N, available P and available K content in soil and also increased effects of crop residues. Crop residues had no significant effect on available P content in soil. Incorporation of WR with SGM and MBR with adequate fertilizer-N is, thus, recommended for building up organic C, kjeldahl-N and available K content in soil.     

Alley cropping Sesbania sesban (L) Merill with food crops in the highland region of Rwanda

Food production in the densely populated Rwandan highlands is impeded by soil erosion and loss in fertility. Alley cropping leguminous shrubs with food crops on contours is purported to minimize the problem and to provide wood and forage. This study reports the effect of Sesbania prunings plus moderate levels of N and P on bean (Phaseolus sp) and maize (Zea mays) yields in alley cropping. Experimental design was a randomized complete block with split-split plots. Main plots were alley width: 2, 4, 6 and 8 m. Phosphorus (P) at 0, 30 and 60 kg P₂O₅/ha occupied the subplot and nitrogen (N) at 0, 30 and 60 kg/ha were assigned at the sub-sub plot level. No P was applied to maize during the second cropping season. Crop yield in kg/ha included the land space taken by hedgerows. Bean yield in 6 m alleys (1100 kg/ha) was about twice that in 2 m alleys (500 kg/ha). Bean responded to N and P. Optimum alley width and N for bean yield were 6 m and 30 kg/ha, respectively. Cuttings from alley hedgerows provided stakes for climbing beans. Maize responded to N but not to residual P. The highest maize yield came from 8 m alleys with 40 kg/ha, but yields from 8 and 6 m alleys with the same N treatment were not significantly different. Maize plants in middle rows were significantly taller than plants in rows adjacent to hedgerows. Maize rust development showed significant alley width and row position effect. There were significantly fewer uredinia in the Sebania alleys relative to the control plots without shrub hedgerows. Rust development on maize in middle rows was significantly greater than development in border rows.     

The relation between biomass yield and linear measures of growth in Sesbania sesban in western Kenya

Various linear measurements were made on 115 provenances of Sesbania sesban var. nubica to establish their relationships with woody and leafy biomass yields of the trees after a year's undisturbed growth. Data were subjected to simple and multiple linear regression analyses. There were significant (P < 0.001) correlations in most cases but particularly so with leafy and total biomass where over 50% of the variations were accounted for by their regression on stem diameter at knee height (DKH). When data for dependent variables were logarithmically transformed, better regression coefficients (over 60%) were obtained for stem diameter at breast height (DBH) and DKH.     

山东皱皮木瓜品种分类探讨

 在多年调查研究基础上，采用“二元分类法”对山东主产区皱皮木瓜资源进行系统分类，形成了2类6群15型(含23个品种)的“2元3级分类系统”。     

不同发酵工艺对资丘木瓜酵素品质的影响

以药食两用的资丘木瓜为主要原料,采用自然发酵、酵母菌-德氏乳杆菌保加利亚亚种-嗜热链球菌先后顺序接种发酵、酵母菌-长双歧杆菌-嗜热链球菌先后顺序接种发酵3种工艺制备木瓜酵素,并对其发酵过程中的3种清除自由基能力、淀粉酶和有机酸进行研究。结果表明,不同发酵工艺制得的木瓜酵素均有较强的抗氧化性,对自由基的清除率在80%以上,其中自然发酵制备的酵素清除自由基清除能力最强,工艺相对稳定;人工接种-嗜热链球菌后可以提高木瓜酵素清除DPPH·和O2-·的能力,分别提高30%和10%;自然发酵的淀粉酶活力最高,大约是人工接种的2号和3号发酵工艺的3倍,有机酸含量也最高,但人工接种发酵工艺所制得酵素产品活菌数比自然发酵的高,其中3号发酵工艺所得酵素产品的益生菌数量是自然发酵的2倍多,2号和3号发酵工艺中增加了乙酸种类。     

不同栽培基质对牛大力根系发育的影响

以不同比例泥土、砂、椰糠、草炭混合作为牛大力栽培基质,并进行盆栽试验,研究不同栽培基质条件下,基质的养分特征及其对牛大力根系生长和膨大状况的影响。结果表明:由草炭+泥土(体积比2∶1)及草炭+椰糠+砂(体积比1∶2∶1)混合的基质p H值较适中,有机质含量与氮磷钾养分含量均较高,养分状况较理想,牛大力根系发达,但膨大块根较少;而泥土与砂混合基质各项指标均比较低,养分比较贫乏,牛大力根系发达,但块根膨大明显。在本研究条件下,基质养分不是根系膨大的关键因素,泥土含量高的基质可能因为较为理想的通气和热量条件而有利于块根的膨大。     

Agroforestry and forestry on the Cape Verde Islands

The geography, socio-economy, climate and agriculture of the Cape Verde Islands are introduced. Forestry and agroforestry provenance trials are described for coastal and inland areas in the semi-arid climate of Cape Verde. Sesbania sesban var. nubica showed promise as a drought tolerant, fast growing agroforestry species and Acacia bivenosa is recommended for soil stabilisation of exposed coastal areas. At a saline coastal site Atriplex lentiformis and A.halimus were the fastest growing of seven Atriplex species.