DNA分子标记在小麦抗条锈性遗传研究中的应用

综述了近年来DNA分子标记在小麦抗条锈性遗传研究中的应用现状和潜力。内容涉及DNA分子标记在基因标记,基因克隆,遗传图谱构建和辅助选择育种等方面的应用,并列举了代表性实例,展望了DNA分子标记技术在小麦抗条锈病研究上的前景。     

Comparative morphology of leaf epidermis in the Chloranthaceae

Leaf epidermis of 23 samples representing 16 species of all the four extant genera of the Chloranthaceae, i.e. Sarcandra, Chloranthus, Ascarina and Hedyosmum , were investigated under both light microscope and scanning electron microscope. Characters of leaf epidermis in this family, such as pattern of epidermal cells, type of stomata, shape of guard cell pairs and cuticular ornamentation, are usually constant in species and thus of great significance in understanding the relationships between and within genera. The previous viewpoints with either Hedyosmum or Chloranthus shown as having the closest affinity with Ascarina seem to be unreasonable. The phylogeny indicated by DNA sequence analysis, which suggested that Ascarina be the sister group of Sarcandra and Chloranthus , and Hedyosmum the sister of the above three genera, is well supported. Within Chloranthus , the traditional division of the genus on the basis of habit seems to be quite unnatural. Evidence from leaf epidermis, just as that from stem anatomy and cytology as well as sequence analysis of ITS region, strongly suggests the separation of the genus into two groups according to the characteristics of androecial organs.     

Components of quantitative resistance in sunflower to Alternaria helianthi

Components of quantitative resistance, spore production, incubation period, infection frequency and mean lesion size were measured in 17 sunflower accessions inoculated with conidia of Alternuria helianthi under controlled conditions. The same accessions were also rated for disease reaction in the field in 1994 and 1995 using a generated epidemic and varied in their disease reactions from highly susceptible to highly resistant. Spearman's ranking of accessions was highly correlated (r = 0.9) for both years; however, the ranking of components measured under controlled conditions with field severity was generally poor. Regression analysis of components with field severity ratings of the accessions showed that mean lesion size was highly correlated (r = O.74) and infection frequency was moderately correlated (r = 0.58) with the field severity ratings taken over the two years. Infection frequency was also well correlated (r = 0.75) with mean lesion size. Spore production and incubation period were poorly correlated with the field severity ratings for both years. An index based on infection frequency and mean lesion size gave a better correlation with the 1995 field severity ratings than either component alone, but in 1994 the index was not as well correlated with field severity as mean lesion size alone. It is suggested that mean lesion size, determined from plants 7–9 days after inoculation could be used to select for resistance to A. helianthi in the greenhouse. Infection frequency could also be used as a predictor of resistance, but to a lesser degree.     

黄顶菊与3种本地植物竞争对丛枝菌根真菌种类和多样性的影响

【目的】外来植物黄顶菊对生态环境和农业经济造成了严重危害,了解黄顶菊与3种不同本地植物种植生长对丛生菌根(AM)真菌群落结构和多样性造成的影响,可以从土壤微生物角度进一步解释黄顶菊的入侵机制。【方法】通过同质园小区试验模拟黄顶菊入侵的生态进程,以黄顶菊和3种本地植物狗尾草、藜、黄香草木樨为研究对象,采用AM真菌的形态学鉴定方法,研究黄顶菊与3种本地植物不同种植方式对AM真菌群落结构和多样性的影响。【结果】(1)黄顶菊根际土壤聚集的AM真菌种类与其伴生本地植物种类有关:黄顶菊与狗尾草混种处理中优势种为网状球囊霉和根内球囊霉,而黄顶菊分别与藜、草木樨混种处理中优势种均为网状球囊霉、根内球囊霉和缩球囊霉;(2)黄顶菊分别与狗尾草和黄香草木樨混种处理中AM真菌种类既高于本地单种处理,也高于黄顶菊单种处理,说明随着黄顶菊的入侵和地上植物多样性的改变,AM真菌种类也发生改变;(3)与3种本地植物单种相比,黄顶菊各混种处理和黄顶菊单种处理中黄顶菊根际土壤根内球囊霉的重要值均增加,表明黄顶菊入侵有利于根内球囊霉的生长和发育。【结论】黄顶菊入侵改变了根际土壤AM真菌的群落结构和多样性,AM真菌的改变既与本地植物种类有关,也与入侵程度有关。     

Streptomyces pulveraceus突变株中福司曲星类似物的分离鉴定及其生物合成途经初探(英文)

福司曲星是一种从Streptomyces pulveraceus分离得到的磷酸酯类、聚酮类抗生素。本文从其突变株(ΔfosJ)分离得到一系列新的福司曲星结构类似物(10～14)。结合各种波谱方法,我们对其结构进行鉴定。由于这些化合物的结构特殊性,初步推断这些化合物可能来自于异常的PKS组合生物合成。     

BMP9经Smad信号通路调控iSCAP成骨/成牙本质分化

目的：研究BMP9是否能够激活 iSCAP细胞中的Smad信号通路,以及Smad信号通路在BMP9诱导iSCAP细胞成骨/成牙本质向分化过程中的作用。方法：首先,采用Western印迹实验检测Ad-BMP9转染iSCAP后Smad1/5/8蛋白的磷酸化水平。随后,利用dnALK1重组腺病毒和BMP9条件培养基作用于iSCAP,Western印迹实验检测Smad1/5/8蛋白磷酸化水平;采用碱性磷酸酶（ALP）活性检测和染色方法分析早期成骨/成牙本质指标变化,茜素红染色法检测钙盐沉积程度;RT-PCR成骨/成牙本质相关基因Runx2、OCN、OPN和DMP1表达的影响。结果：BMP9可上调iSCAP中Smad1/5/8的磷酸化水平;dnALK1抑制BMP9条件培养基作用后,可抑制Smad1/5/8的磷酸化,iSCAP细胞中早期成骨/成牙本质标志物ALP活性和晚期成骨/成牙本质标志钙盐结节减少,重要成骨转录因子Runx2基因表达减少,成骨/成牙本质相关基因OCN、OPN、DMP1的表达也受到了抑制。结论：Smad信号通路在BMP9诱导iSCAP成骨/成牙本质过程中存在并起着重要作用。     

云南松三种同域共存切梢小蠹梢转干期的空间分布格局

分布在我国西南地区的横坑切梢小蠹,云南切梢小蠹和短毛切梢小蠹同域危害寄主云南松,给林业生产带来巨大损失。为探讨同域切梢小蠹种群在共存下对其空间分布格局的影响,采用传统聚集指标法和地统计学方法研究了三者在梢转干期不同受害云南松纯林树冠中的空间分布型。结果表明重度受害样地中云南切梢小蠹种群密度显著高于横坑切梢小蠹,在轻度受害样地则相反;传统聚集指标法结果显示同域共存的3种切梢小蠹种群在不同受害程度云南松中均为聚集分布,横坑切梢小蠹和云南切梢小蠹聚集是由环境因素和昆虫本身的聚集习性引起;地统计学结果表明除重度受害样地中短毛切梢小蠹呈随机分布外,其余切梢小蠹在不同种群密度下均呈聚集分布;除重度受害样地横坑切梢小蠹外,其他小蠹的空间依赖范围为4.01—7.45 m。横坑切梢小蠹和云南切梢小蠹在不同受害林分中拟合的半变异函数模型在球形模型和高斯模型之间转换。同域共存关系不影响不同种群密度下的切梢小蠹种群空间分布类型,但影响其半变异函数模型和理论参数。     

三峡库区消落带4种典型草本植物的生态化学计量特征

为研究三峡水库消落带优势植物的养分利用特征及其对生境的适应策略,选择消落带分布最多的4种草本植物为研究对象,分析了植物根、茎、叶的碳(C)、氮(N)、磷(P)、钾(K)含量和化学计量比特征。结果表明:(1)相比陆地系统和自然湿地系统,消落带植物具有较低的C含量和较高的N、P、K含量,C/N、C/P、C/K均较低,表明植物具有低固碳和高养分积累、低养分利用效率和高生长速率的特征;(2)4种植物的养分含量和计量比存在一定差异,其中狗牙根具有较低的N、P、K含量和较高的C/N、C/P、C/K,且变异系数均低于其他3种植物,其低养分需求、高养分利用效率以及较强的内稳性可能是其在库区分布最广的重要机制;(3)4种植物在不同器官的养分分配策略相似,均表现为叶片C含量低于根和茎,而N、P、K含量则显著高于根、茎;同时,与根、茎相比,叶片C/N、C/P、C/K较低,N/P、N/K较高,且在不同生境条件下变异系数较小,表现出相对较高的稳定性;(4)落消带植物的养分含量及计量比从全库区上游至下游的空间变异性较强,其中N、C/N、N/P变异性较大,而C、P、K变异性较小,表明植物N含量受生境变化的影响较大,...     

主要尿蛋白(MUPs)参与化学信息交流和糖脂代谢

主要尿蛋白（MUPs）属于脂质运载蛋白家族,具有保守的中心疏水β链桶状特征性结构域,具有调节种属内与种属间个体间化学信息交流的功能.MUPs主要在肝合成并分泌入血,作为载体与信息素等亲脂性小分子结合,延长其半衰期,一并从肾过滤排泄入尿液,延缓尿迹中信息素的挥发,从而延长信息素的作用时间.啮齿类动物的MUPs本身具有高度多态性,能够发挥类似信息素的作用直接编码个体信息,调节种属内的生物活动.此外,MUPs还能够发挥利它素的功能引起其它种属的畏惧反应.新近研究发现,MUPs受到机体营养状态的调节,与代谢性疾病及糖脂代谢密切相关,但机制尚不清楚.MUPs的功能和机制探索对于化学信息交流与糖脂代谢研究具有重要意义.本文旨在对MUPs的最新研究结果展开简要综述及讨论.