祁连山地区植被特征及其分布规律

分析和讨论了祁连山地区主要植被类型及其分布特征。祁连山地区随着青藏高原的强烈隆升表现为整体抬升,植被具有明显的生态地理边缘效应特征和高原地带性规律。该区植被虽然受到四周的较大影响,但各类高寒植被占有绝对优势,表现出与青藏高原植被整体明显的相似性和广泛的一致性。另一方面,本区植被也有其特殊性及与高原面存在一些差异。因此,建议把祁连山地区做为青藏高原植被区的次一级独立单元     

质体醌重组的D1／D2／Cytb559复合物的荧光衰减动力学和光破坏作用

光系统Ⅱ反应中心Ｄ１／Ｄ２／Ｃｙｔｂ５５９ 在分离纯化过程中失去了电子受体ＱＡ 和ＱＢ,人工合成的质体醌可以与Ｄ１／Ｄ２／Ｃｙｔｂ５５９ 复合物发生重组。癸基质体醌（ＤＰＱ）与Ｄ１／Ｄ２／Ｃｙｔｂ５９９ 复合物的重组导致该复合物的荧光强度下降及发射光谱蓝移,同时两个与光化学活性相关的长寿命（２４ ｎｓ和７３ ｎｓ）荧光衰减组分占整个荧光的百分数下降,这些结果表明ＤＰＱ作为Ｐｈｅｏ－ 的电子受体,限制了Ｐ６８０＋ ·Ｐｈｅｏ－ 的电荷重组。ＤＰＱ 的加入对Ｄ１／Ｄ２／Ｃｙｔｂ５５９复合物中Ｃｈｌａ 分子的光破坏敏感性影响不大,但β－胡萝卜素在加入ＤＰＱ 之后可以被光照破坏,这个过程可能与β－胡萝卜素的生理功能相关。     

Immunolocalization of tenascin and cellular fibronectins in diverse glomerulopathies

Frozen samples of minimal change glomerulopathy (MCG), and of membranous, segmental and diffuse lupus glomerulonephritis (MGN, SGN, DLGN) were studied to assess the distribution of tenascin (Ten), and the extradomains A and B (EDA-and EDB-) and oncofetal (Onc-) isoforms of cellular fibronectin (cFn). Cryosections were immunostained by the ABC method with specific monoclonal antibodies. In MCG, mesangial Ten and EDA-cFn reactions were increased. In MGN, mesangial Ten and EDA-cFn staining was enhanced except in segmental scars; convincing reactions were seen in cases with membranous transformation; spikes stained strongly. In SGN, variably intense staining for Ten and all cFn isoforms was seen in glomerular necrosis, proliferation and crescents; parietal epithelium EDA-cFn staining was noted. In DLGN, strong and extensive mesangial Ten and EDA-cFn staining was seen as were focal EDB-and Onc-cFn reactions. Parietal cells with and without crescents stained variably with all Mabs. Obsolete glomeruli were unreactive save for rare periglomerular Ten rims. Interstitial inflammation and fibrosis in MGN, SGN and DLGN had moderate to strong Ten and EDA-cFn staining with rare traces of EDB-and Onc-cFn. We conclude that enhanced Ten and EDA-cFn is a potentially reversible response to glomerular injury whereas the expression of EDB-and Onc-cFn apparently result from necrosis and/or cellular proliferation which lead to scarring. And, while mesangial cells are the major source of these molecules, epithelial cells might also partake in their synthesis.     

中蜂处女王性成熟日龄及其交尾习性的探讨

本研究对210只人工培育的出房后1,2,3,4,6,8．10日龄的中蜂处女王受精囊液的pH值进行测定．结果表明,1日龄处女王受精囊液的pH值平均为7．7,2日龄为8．5,从3日龄开始达到最高值8.8．并保持稳定状态,由此判断出房后3日龄的中蜂处女王性已成熟．通过对72只中蜂处女王交尾飞行的观察,结果表明,蜂王交尾日龄多为6-8日．最早为4日龄,最迟为16日龄;处女王认巢飞行持续时间平均为7．4分钟,交尾飞行平均为21．5分钟：处女王连续交尾飞行1-3次,有9只处女王在一天里进行2次交尾飞行．     

Small-spored Alternaria spp. (section Alternaria) are common pathogens on wild tomato species

The wild relatives of modern tomato crops are native to South America. These plants occur in habitats as different as the Andes and the Atacama Desert and are, to some degree, all susceptible to fungal pathogens of the genus Alternaria. Alternaria is a large genus. On tomatoes, several species cause early blight, leaf spots and other diseases. We collected Alternaria-like infection lesions from the leaves of eight wild tomato species from Chile and Peru. Using molecular barcoding markers, we characterized the pathogens. The infection lesions were caused predominantly by small-spored species of Alternaria of the section Alternaria, like A. alternata, but also by Stemphylium spp., Alternaria spp. from the section Ulocladioides and other related species. Morphological observations and an infection assay confirmed this. Comparative genetic diversity analyses show a larger diversity in this wild system than in studies of cultivated Solanum species. As A. alternata has been reported to be an increasing problem in cultivated tomatoes, investigating the evolutionary potential of this pathogen is not only interesting to scientists studying wild plant pathosystems. It could also inform crop protection and breeding programs to be aware of potential epidemics caused by species still confined to South America.     

Nitric Oxide Enhances Salt Tolerance in Tomato Seedlings by Regulating Endogenous S-nitrosylation Levels

Salinity impairs plant growth and development, thereby leading to low yield and inferior quality of crops. Nitric oxide (NO) has emerged as an essential signaling molecule that is involved in regulating various physiological and biochemical processes in plants. In this study, tomato seedlings of Lycopersicum esculentum L. “Micro-Tom” treated with 150 mM sodium chloride (NaCl) conducted decreased plant height, total root length, and leaf area by 25.43%, 24.87%, and 33.67%, respectively. While nitrosoglutathione (GSNO) pretreatment ameliorated salt toxicity in a dose-dependent manner and 10 µM GSNO exhibited the most significant mitigation effect. It increased the plant height, total root length, and leaf area of tomato seedlings, which was 31.44%, 20.56%, and 51.21% higher than NaCl treatment alone, respectively. However, NO scavenger 2-(4-carboxyphenyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide potassium (cPTIO) treatment reversed the positive effect of NO under salt stress, implying that NO is essential for the enhancement of salt tolerance. Additionally, NaCl?+?GSNO treatment effectively decreased O^2? production and H₂O₂ content, increased the levels of soluble sugar, glycinebetaine, proline, and chlorophyll, and enhanced the activities of antioxidant enzymes and the content of antioxidants in tomato seedlings in comparison with NaCl treatment, whereas NaCl?+?cPTIO treatment significantly reversed the effect of NO under salt stress. Moreover, we found that GSNO treatment increased endogenous NO content, S-nitrosoglutathione reductase (GSNOR) activity, GSNOR expression and total S-nitrosylated level, and decreased S-nitrosothiol (SNO) content under salt stress, implicating that S-nitrosylation might be involved in NO-enhanced salt tolerance in tomatoes. Altogether, these results suggest that NO confers salt tolerance in tomato seedlings probably by the promotion of photosynthesis and osmotic balance, the enhancement of antioxidant capability and the increase of protein S-nitrosylation levels.

     

拟南芥ACOL8基因在乙烯合成与响应中的功能分析

植物激素乙烯在多种生理生化过程中发挥重要作用,但其在特定组织器官中的合成机制尚不完全清楚。拟南芥中存在12个功能未知的ACC氧化酶类似蛋白（ACO-like homolog,ACOL）,运用基因定点编辑技术构建了ACOL8的功能丧失型突变体,发现该基因的突变削弱了经典的乙烯“三重反应”。与野生型相比,突变体黄化幼苗下胚轴及主根的长度显著增加,这与突变体对外源ACC的敏感性下降现象一致。同时还发现ACOL8基因的表达受乙烯信号的正反馈调控,EIN3过表达增强其表达水平,而etr1-3的突变则产生相反效应。再者,在正常条件下,ACOL8基因的突变并未影响拟南芥的生长;但在盐胁迫条件下,突变体的根冠比显著下降,这说明该基因参与植物的盐胁迫响应。综上,这些结果说明ACOL8可能具有ACC氧化酶的功能,参与乙烯的合成与响应。     

罗非鱼对微型生态系统营养物水平的影响

本文总结了罗非鱼不同放养密度的微型生态系统中N、P浓度及P分布动态观测结果。在罗非鱼的影响下,微型生态系统中氨氮、颗粒磷和总磷浓度不同程度地高于对照组,而正磷酸盐浓度和沉积物磷的量显著地低于对照组。不同密度组某些指标的观测值虽有显著差异,但未见任何指标依罗非鱼放养密度而有规律地变动。微型生态系统中正磷酸盐浓度同浮游动、植物密度和初级生产力显著相关,氨氮浓度与浮游植物密度之间亦有显著的相关关系。然而,浮游植物密度与总磷浓度之间不存在营养级联假说所预见的下行影响,相反有前者决定于后者的上行影响的趋向。微型生态系统中P分布的变化可揭示罗非鱼促进系统中营养物循环,从而加速其富营养化的主要机制。