利用蚕豆根尖微核技术检测武汉南湖水质污染状况

[目的]研究南湖不同片区的水质污染程度和总体水质对生物的危害程度。[方法]利用蚕豆根尖微核技术对武汉市南湖水域具有代表性的21个水样进行动态监测和评价。[结果]与阴性对照组根尖的微核率相比,试验组各处理的根尖微核率都有明显升高,并根据季节和地点呈一定的周期性变化规律:夏、秋季比冬、春季节的污染大;靠近学校、居民区湖区比人口较少地段的湖区污染大。[结论]南湖水质较差,整个湖区为中度以上污染,应及时加以治理。     

火龙果茎腐病致病菌的鉴定

为弄清火龙果茎腐病的病原和分类地位,并进一步为该病害的有效防治提供理论依据。本研究从琼海、临高、陵水等地广泛采集病样。经田间症状调查、组织纯化培养、病原形态观察、致病力测定、真菌ITS序列和系统进化分析,鉴定了该病害的病原。结果表明:病原分离物具有典型的镰刀菌形态特征,菌丝浓密,产生紫色素,小型分生孢子新月形,大型分生孢子镰刀形,有多个隔;而在ITS序列分析中,代表菌株47A4和47A5与NCBI数据库中尖孢镰刀菌的多条ITS序列(登录号分别为KJ653447.1, DQ535184.1和KM268692.1)相似性达100%;系统进化树上,47A4和47A5与尖孢镰刀菌聚在同一分支上,遗传距离最近,而与非纯培养镰刀菌克隆3.91E在不同分支上,遗传距离远。结合形态特征、序列分析和系统进化分析,将火龙果茎腐病的病原鉴定为尖孢镰刀菌(Fusarium oxysporum)。研究结果对火龙果茎腐病流行规律、致灾机理的研究具有重要的指导作用。     

不同小麦品种(系)抗倒伏性状多样性分析

为了综合评价不同小麦材料的不同生育时期抗倒性,明确影响小麦倒伏的关键因素,以147份我国育成的主推小麦品种及新育成的小麦品种（系）为研究对象,在开花期、灌浆期和乳熟期测定其10个倒伏性相关性状,并利用主成分分析和聚类分析法对这些小麦材料抗倒性进行综合评价。结果表明,10个抗倒伏相关性状在不同基因型间、气候因素间及生育时期间均存在显著的变异;在不同生育时期,性状间的相关性基本一致,均表现为基部茎节壁厚度、实心度、茎秆强度对小麦的抗倒伏性具有一定的积极作用,株高、重心高度、基部茎节长度、髓腔直径具有一定的消极作用。主成分分析显示,茎秆强度是影响植株抗倒性的最关键性状。基于三个生育时期主成分的综合因子得分的聚类分析显示,有70份材料的综合抗倒性优良,其中部分新育成小麦材料抗倒性表现优异,可作为小麦强秆抗倒改良育种资源使用。     

花期干旱胁迫后限源疏库对玉米光合性能和茎流的影响

开展玉米花期干旱限源疏库试验,探索减轻花期干旱胁迫的技术途径。结果表明,去根叶组叶片可显著减少植株前期茎流,抑制叶片蒸腾,对穗5叶的叶绿素相对含量、光系统Ⅱ最大光化学效率(Fv/Fm)和潜在活性(Fv/Fo)影响不显著,正常灌溉情况下还有利于延缓玉米花后穗5叶的衰老,并促进后期茎流超补偿;去耕作层1/4根系会加剧前期植株水分的散失,干旱时浅中耕的措施是不可取的,并抑制后期茎流,增大Fv/Fm;去穗虽然可以显著减少茎流,抑制叶片蒸腾,但是因缺少库需求而加速花后穗5叶的叶绿素相对含量、Fv/Fm和Fv/Fo下降,促使叶片衰老。品种间对花期干旱胁迫后不同的限源疏库处理表现出显著差异,这是生物节水和作物补偿生长的生理基础。     

薰衣草茎段再生体系的建立

以薰衣草带芽茎段为外植体,探讨不同激素种类与水平等因素对其愈伤诱导、不定芽分化、增殖与不定根形成的影响,并筛选了薰衣草试管苗过渡移栽的适宜基质等。试验结果表明:不定芽启动培养以MS+BA1.0~2.0mg/L+蔗糖30g/L+琼脂6.5g/L为宜;继代增殖以MS+BA1.0~2.0mg/L+IBA0.25mg/L+GA1.0mg/L+蔗糖30g/L+琼脂6.5g/L为宜;不定根分化以White+IBA0.4mg/L+蔗糖20g/L+琼脂6.5g/L或White+NAA0.8mg/L+蔗糖20g/L+琼脂6.5 g/L为宜。     

胚胎干细胞的研究进展及应用前景

干细胞(Stem Cell)是一类具有分化潜能和自我复制的早期未分化细胞。胚胎干细胞(Embryonic stem cells,ES细胞)是一种早期胚胎内细胞团(inner cell mass,ICM)或原始生殖细胞(primordial germ cell,PGC)经体外分化抑制培养,分离和克隆得到的具有发育全能性的高度未分化细胞。本文综述了胚胎干细胞的形态学、生长特性、免疫学鉴定方法,ES细胞抑制分化和诱导分化的机理以及饲养层、血清和细胞因子等影响胚胎干细胞分离克隆的因素,并进一步阐述了胚胎干细胞的应用前景以及存在的问题。     

“巨峰”葡萄热处理茎尖培养技术研究

以"巨峰"葡萄为试材,经热处理后取其茎尖进行离体培养,通过调整激素的种类和浓度,筛选出了适宜"巨峰"葡萄茎尖分化和生根的培养基;通过对不同移栽基质的研究,筛选出了移栽成活率较高的基质配方。结果表明:38℃热处理时葡萄苗发芽率最高,可达86.67%;以GS为基本培养基,附加BA 0.5mg/L与NAA 0.1mg/L,最适宜于"巨峰"葡萄茎尖分化成苗,分化率可达70.00%;生根培养基以GS+IBA 0.06mg/L的生根率最高。适宜"巨峰"葡萄茎尖组培苗移栽的基质为河沙1份+水苔1份。     

Breast cancer stem cells cultured without insulin and effect of estrogen induction

AIM:To determine whether suspension culture medium without insulin can be used to feed breast cancer tumorsphere, or not. METHODS:MCF7 cells were used to build tumorsphere. The morphological changes, CD44+ CD24- expression, aldehyde dehydrogenase 1 (ALDH1) expression and multiple division ability were measured to identify the breast cancer stem cells and to detect the function of 17β-estradiol (E2β) in tumorsphere of MCF7 cells. RESULTS:The tumorshere, each containing 30 to 60 cells, was obtained by the method of insulin-removal suspension culture. These cells were cytokeratin 18 and CD10 proteins positive, and the number of CD44+ CD24- cells and ALDH1 protein expression were significantly higher than the adherent cultured cells (P<0.05). Using 10-10 mol/L E2β to treat the tumorshere for 7 d, the tumor cell number and volume were significantly increased. Using 10-10 mol/L E2β to treat the tumorshere for 24 h, the CD44+ CD24-cells and ALDH1 protein expression were significantly higher than those in non-treatment group (P<0.05). CONCLUSION: Suspension culture medium without insulin can be used to feed breast cancer tumorsphere. These tumorsphere could be used as a model to determine the function of E2β in breast cancer stem cell research.     

Calcium nutrition of the sugarbeet

Abstract

When sugarbeet seedlings are transferred from a complete nutrient solution to one from which Ca has been withheld, the rootlets and tops fail to develop. The same transfer at the eight‐leaf stage causes the rootlets to become stubby and swollen at the tips and blade expansion becomes modified; particularly the upper portions of the blades attaining nearly full development, which pucker and often develop a cupping or hooding effect; a unique symptom characteristic of Ca deficiency. As each new leaf develops, the blade area becomes smaller until only a black tip remains at the apex of the petiole, which is the symptom referred to as tip‐burn for this petiole and the successively . shorter petioles formed as Ca deficiency increases in severity. Strangely, these symptoms also appear during periods of rapid growth when the nutrient solution contains as much as 10 to 28 milliequivalents per liter of Ca or when soils are high in Ca. This implies that Ca absorption and possibly translocation limits the Ca supply at the growing point. Increasing Mg in the nutrient solution decreases Ca uptake and increases Ca deficiency. Potassium deficiency, unexpectedly, induces Ca deficiency apparently by decreasing the translocation of Ca to the growing point.

These phenomena suggest the hypothesis that when ion absorption takes place from the root exchange site that has the affinity for H > Ca > Mg > K > Na, then the H generated internally replaces, and the roots absorb, Na, K and Mg preferentially. Externally, Ca would be adsorbed preferentially from the nutrient solution by the exchange complex, and with the addition of Mg, it would compete for the common adsorption site of Ca and limit Ca absorption internally. Under these conditions potassium‐deficient nutrient solutions would not induce Ca deficiency by decreasing Ca absorption but rather by decreasing Ca translocation. Theoretically, Ba would replace H more readily than Ca on the exchange complex, and therefore, Ba would be adsorbed preferentially and Ca uptake would increase. This effect of Ba was verified experimentally.

Since the translocation of ⁴⁵Ca to the growing point was found to be unrestricted under Ca‐sufficient and Ca‐deficient conditions and since the formation of insoluble Ca compounds such as phosphate or oxalate did not account for the Ca deficiency at the growing point, the cause of the Ca deficiency at the growing point is most likely the higher priority of the storage root for Ca over tops when leaf blades and storage root are both expanding rapidly. However, Ca retransport from older to younger parts of the sugarbeet plant may be restricted by the formation of Ca phosphate under Ca‐deficient conditions and Ca oxalate under Ca‐sufficient conditions.

Calcium deficiency increases net photosynthesis per unit blade area initially, probably because of blade puckering, but not on a per unit chlorophyll basis.     

中华芦荟的离体快繁技术研究

[目的]探索芦荟的离体快繁技术,为芦荟的组织培养提供试验依据。[方法]以盆栽中华芦荟的嫩茎尖为外植体,MS为基本培养基,不同的增殖阶段添加不同的植物激素进行离体快繁试验。[结果]培养30 d后,3瓶被污染,4瓶不长愈伤组织,13瓶在芽基部产生圆球状浅黄色的愈伤组织。在诱导芽分化约20 d后,2瓶被污染,11瓶开始芽点分化。3.00 mg/L 6-BA的处理效果最佳。诱导生根11 d后,1瓶被污染,2瓶出现叶子干焦的现象,17瓶长势良好。中华芦荟愈伤组织诱导的适宜培养基为MS＋6-BA 2.50 mg/L＋NAA0.15 mg/L,诱导率为60%;丛生芽分化及继代的适宜培养基为MS＋6-BA 3.00 mg/L＋NAA 0.10 mg/L,诱导率为85%;生根的适宜培养基为MS＋6-BA 0.30～0.50 mg/L＋IBA 0.20 mg/L＋活性炭0.5%。[结论]该研究为芦荟的快繁提供了初步的理论依据。