甘蔗内生菌分离鉴定及功能多样性研究

为探究甘蔗内生菌多样性组成及相关特性,本研究采用稀释涂板法分离并结合形态观察和分子标记(gyrB,rpoB, ITS, 16S rDNA)进行鉴定。结果表明,从12个栽培品种(系)和5个野生种无性系的根、茎、叶组织中共分离到细菌589株、放线菌34株和真菌46株;细菌中固氮菌有41株,溶磷菌有98株,解钾菌有52株,对黄曲霉和禾谷镰刀菌具有拮抗作用分别有44株和35株。内生细菌分属21个属,其中芽孢杆菌属、伯克氏菌属、肠杆菌属和泛菌属为优势属;内生真菌分属于枝顶孢属、链格孢属、曲霉属、镰刀菌属、枝孢属等17个属,而放线菌仅为链霉菌属。具有潜在植物益生功能的菌株主要集中在芽孢杆菌属、伯克氏菌属、肠杆菌属、假单胞菌属、不动杆菌属、类芽孢杆菌属及泛菌属。本研究显示甘蔗栽培品种(系)和野生种无性系均含有丰富的内生菌资源,且栽培品种(系)所含内生菌在数量和多样性上均高于野生种无性系;12个栽培品种(系)间所分离到的内生细菌大部分相同,但也存在差异。通过初步的功能鉴定,筛选出一些具有应用潜力的益生微生物,为开发相应功能的生物菌剂奠定基础。     

全国甘蔗野生种质资源的采集和考察

１９８５～１９９３年在全国进行了甘蔗野生种质资源的采集和考察。采集到甘蔗亚族（Ｓａｃｃｈａｒｉｎａｅ）内９个属１８个种的无性系共８２４份，种植在云南农业大学校园内（昆明黑龙潭），建立了甘蔗资源圃。考察了甘蔗属（Ｓａｃｃｈａｒｕｍ）、蔗茅属（Ｅｒｉａｎｔｈｕｓ）、河八王属（Ｎａｒｅｎｇａ）和芒属（Ｍｉｓｃａｎｔｈｕｓ）中主要野生种的地理分布、开花期、形态特征、繁殖方式、生态适应性、锤度和种质流失的情况。探明了割手密（Ｓ．ｓｐｏｎｔａｎｅｕｍＬ．）和斑茅（Ｓ．ａｒｕｎｄｉｎａｃｅｕｍＲｅｔｚ）的开花期与原产地纬度和海拔的相关，探索了割手密与蔗茅（Ｅ．ｆｕｌｖｕｓＮｅｅｓ）茎秆锤度与地理分布的联系。     

甘蔗与蔗茅杂交亲本及后代材料的抗旱性鉴定

研究旨在筛选出优良抗旱育种材料,为今后甘蔗抗旱育种和抗旱栽培技术提供重要的理论依据。采用盆栽干旱处理,测定蔗茅野生种无性系、甘蔗栽培品种（系）及其杂交后代共12份材料苗期与抗旱相关的8项生理生化指标,利用极点排序法对供试材料的抗旱性进行了综合评价。结果表明：干旱胁迫下,12份供试材料的Pro、MDA、SS及PMP均呈上升趋势,SP、Chl和SOD活性呈下降趋势,CAT活性有升有降。极点排序法分析表明,12个供试材料的抗旱强弱为：‘蔗茅99-2’>‘蔗茅99-1’>‘蔗茅99-4’>‘蔗茅I91-8’>‘蔗茅99-3’>‘蔗茅90-29’>‘滇蔗01-58’>‘滇蔗04-14’>‘滇蔗02-39’>‘蔗茅II91-2’>‘新台糖10’>‘崖城89-9’,说明蔗茅优质抗旱性状可以通过基因渗透方式传递给后代。在苗期干旱胁迫下,‘蔗茅99-2’在渗透调节等方面表现出积极的生理响应。     

Identification and pathogenicity of Neophysopella species associated with Asian grapevine leaf rust in Brazil

Asian grapevine leaf rust (AGLR) causes severe crop losses in Brazilian viticulture, mainly in latitudes <25°S. The purpose of this study was to identify the pathogen(s) involved with AGLR in Brazil, based on phylogenetic and morphological analysis and pathogenicity tests. In total, 56 monouredinial isolates from six Brazilian states were identified using the internal transcribed spacer 2 and the large subunit rRNA gene D1/D2 regions. All 50 isolates from the south-central region were classified as Neophysopella tropicalis, and the other six isolates from the north-east region as Neophysopella meliosmae-myrianthae. This result provides evidence that two pathogen introductions from different sources may have occurred in the country. For both species, paraphyses were cylindrical, incurved, aseptate, and hyaline, while urediniospores were short-pedicellate, obovoid or obovoid-ellipsoid, with the wall colourless or pale yellowish, evenly echinulate. Representative isolates from both species caused typical AGLR symptoms on Vitis vinifera 'Merlot' and V. labrusca 'Niagara Rosada'. Overall, regardless of the Neophysopella species, isolates caused similar leaf disease severities. Higher disease severity was observed in Niagara Rosada (average of 40.3% of diseased leaf area) compared to Merlot (20.5%). This study reports, for the first time, the characterization of Neophysopella species associated with AGLR in Brazil.     

Milk production and composition,food consumption,and energy balance of postpartum crossbred Holstein-Gir dairy cows fed two diets of different energy levels

The objective of this study was to evaluate the production, consumption, and energy balance parameters of primiparous 3/4 and 7/8 Holstein × Gir (HG) dairy cows fed two diets of differing energy levels during the postpartum period. At the beginning of the study, 28 days prepartum, the average weight of both genetic groups was 498?±?12 kg and body condition score (BCS) was 3.5?±?0.05. At the end of the study, 61 days postpartum, the 3/4 HG cows had higher weight and body condition scores than the 7/8 HG (456?±?8 and 429?±?8 kg and 3.13?±?0.03 and 2.94?±?0.03 BCS for 3/4 HG and 7/8 HG, respectively). Milk from cows fed the high-energy diet had higher percentages of fat, protein, lactose, and total dry extract than cows fed the low-energy diet. Cows fed the high-energy diet had higher net energy intake (95.3?±?1.9 vs. 88.1?±?2.1 MJ/day) and higher energy balance (3.64?±?2.13 vs ??6.02?±?2.30 MJ/day). The 3/4 HG cows displayed higher energy for maintenance (33.1?±?0.4 MJ/day) than the 7/8 HG (31.5?±?0.5 MJ /day). In conclusion, although the primiparous 3/4 HG were heavier than the 7/8 HG and had a higher body condition score, no differences in milk produced up to 60 days postpartum were observed. The higher energy diet during the postpartum period increased energy balance, resulting in higher production of milk fat, protein, and lactose.

     

芥菜型油菜(Brassica Juncea)杂种优势利用的研究

1973年,本院发现芥菜型油菜雄性不育株后,经连续几年研究,1975年育成了欧新 A 不育系,欧新 B 保持系和74243—6恢复系,实现了芥菜型“三系”配套。多年来连续测定表明,育成的芥菜型“三系”表现育性稳定,欧新 A 不育系的不育株率达100%,单株自交结实指数平均在0.000—0.103之间。恢复株率为99.54～100%,F_1杂种有较强的苗期优     

甘蔗作为能源作物的优势分析及前景展望

与其他能源作物相比,能源甘蔗在原料供应、乙醇产量、生产成本及加工技术等方面具有明显优势,发展前景广阔。能源乙醇生产有利于蔗糖产业的持续发展,促进农业产业结构调整,稳定和提高农民收入。当前,发展甘蔗燃料乙醇产业应重视解决品种选育、工艺改进、政策扶持等问题。     

Spatial patterns of soil attributes and components in a mangrove system in Southeast Brazil (São Paulo)

Purpose

Among environmental factors governing innumerous processes that are active in estuarine environments, those of edaphic character have received special attention in recent studies. With the objectives of determining the spatial patterns of soil attributes and components across different mangrove forest landscapes and obtaining additional information on the cause–effect relationships between these variables and position within the estuary, we analyzed several soil attributes in 31 mangrove soil profiles from the state of São Paulo (Guarujá, Brazil).

Materials and methods

Soil samples were collected at low tide along two transects within the Crumahú mangrove forest. Samples were analyzed to determine pH, Eh, salinity, and the percentages of sand, silt, clay, total organic carbon (TOC), and total S. Mineralogy of the clay fraction (<2 mm) was also studied by X-ray diffraction analysis, and partitioning of solid-phase Fe was performed by sequential extraction.

Results and discussion

The results obtained indicate important differences in soil composition at different depths and landscape positions, causing variations in physicochemical parameters, clay mineralogy, TOC contents, and iron geochemistry. The results also indicate that physicochemical conditions may vary in terms of different local microtopographies. Soil salinity was determined by relative position in relation to flood tide and transition areas with highlands. The proportions of TOC and total S are conditioned by the sedimentation of organic matter derived from vegetation and by the prevailing redox conditions, which clearly favored intense sulfate reduction in the soils (～80% of the total Fe is Fe-pyrite). Particle-size distribution is conditioned by erosive/deposition processes (present and past) and probably by the positioning of ancient and reworked sandy ridges. The existing physicochemical conditions appear to contribute to the synthesis (smectite) and transformation (kaolinite) of clay minerals.

Conclusions

The results demonstrate that the position of soils in the estuary greatly affects soil attributes. Differences occur even at small scales (meters), indicating that both edaphic (soil classification, soil mineralogy, and soil genesis) and environmental (contamination and carbon stock) studies should take such variability into account.

     

New Insights on the Terpenome of the Red Seaweed Laurencia dendroidea (Florideophyceae,Rhodophyta)

The red seaweeds belonging to the genus Laurencia are well known as halogenated secondary metabolites producers, mainly terpenoids and acetogennins. Several of these chemicals exhibit important ecological roles and biotechnological applications. However, knowledge regarding the genes involved in the biosynthesis of these compounds is still very limited. We detected 20 different genes involved in the biosynthesis of terpenoid precursors, and 21 different genes coding for terpene synthases that are responsible for the chemical modifications of the terpenoid precursors, resulting in a high diversity of carbon chemical skeletons. In addition, we demonstrate through molecular and cytochemical approaches the occurrence of the mevalonate pathway involved in the biosynthesis of terpenes in L. dendroidea. This is the first report on terpene synthase genes in seaweeds, enabling further studies on possible heterologous biosynthesis of terpenes from L. dendroidea exhibiting ecological or biotechnological interest.