Effects of Salinity Stress on the Seminal Root Tip Ultrastructures of Rice Seedlings (Oryza sativa L.)

Abstract

Growth and structural changes in the seminal root tip of rice seedlings (Oryza sativa L. cv. Nipponbare) in response to NaCl salinity were studied. Seedlings were grown in agar medium with 0, 0.1, 0.3, 1.0, 2.0 and 3.0% NaCl(agar culture), and in water with 0, 0.01, 0.03, 0.06 and 0.1% NaCl (water culture). Seedling growth was significantly suppressed by higher concentrations of NaCl. The effect of NaCl appeared faster in water culture than in agar culture. In both agar and water cultures, root growth was markedly suppressed over shoot growth. Under saline conditions, epidermis, cortex and root cap cells appear to be damaged to a greater extent than the meristem and stelar cells. The most notable ultrastructural change in response to salinity was the development and increment of vacuoles, which seem to provide a space for accumulation of excess ions. Many electron dense deposits were observed in the larger vacuoles of the epidermal and cortical cells. Under saline conditions, cell wall thickening of the epidermis, an increase in endoplasmic reticulum, myelin figures, less compact Golgi bodies and inhibited production of Golgi vesicles were also observed.     

Potato Stolon and Tuber Growth Influenced by Nitrogen Form

Abstract

Potato tuber initiation and its growth are key processes determining tuber yield, which are closely related to stolon growth, and are influenced by many factors including N nutrition. We investigated the influences of different forms of nitrogen (N) on stolon and tuber growth in sand culture with a nitrification inhibitor during 2010 – 2011, and using two potato cultivars. Plants supplied with NO₃-N (N as nitrate, NO₃^-) produced more and thicker stolons than those supplied with NH₄-N (N as ammonium, NH₄⁺) at tuber initiation stage. In the plants fed NO₃-N, the stolon tips swelled or formed tubers earlier and produced more tubers than in those fed with NH₄-N. However, no significant difference was observed among N forms in terms of tuber yield at harvest, this may have been because of the shoot growth rate at tuber initiation stage was lower in the plants fed NO₃-N. During the tuber bulking stage, the difference in shoot DWs among N forms began to decrease, and the shoot DW of plants fed NO₃-N was even heavier than those fed NH₄-N in some cases. The influence of N form on potato plant growth may therefore vary with the potato growth stage.     

自来水厂水源水及饮用水水质评价

运用蚕豆根尖细胞微核监测技术,以微核千分率为指标,对武汉市某自来水厂的水质进行评估.结果表明,随着暴露时间的延长,各取样点的蚕豆根尖微核千分率显著升高,且与对照组相比具有显著差异.选取暴露32 h的微核千分率计算其污染指数,判定该厂水源水和中间水为中度污染,自来水为轻度污染.因此,该厂作为武汉市饮用水的重要来源,其水质存在一定程度的污染,具有致细胞突变性.     

铁皮石斛茎尖脱毒组培快繁技术研究

[目的]研究铁皮石斛的茎尖脱毒组培快繁技术.[方法]参考其他作物的脱毒技术对铁皮石斛进行脱毒组培研究.[结果]培养基为MS＋ 0.2 mg/L NAA＋ 0.3 mg/L 6-BA时,茎尖的愈伤组织诱导率和分化率最高.[结论]该方法为今后进一步探讨铁皮石斛的脱毒组培快繁技术奠定了基础.     

矮牵牛海藻糖-6-磷酸合酶基因 PhTPS6的克隆与表达分析

以矮牵牛(Petunia hybrida var.Mitchell)为材料,利用PCR方法克隆得到海藻糖-6-磷酸合酶基因6(TPS6)(Trehalose-6-phosphate synthase 6)的同源基因PhTPS6。生物信息学分析显示:该基因cDNA全长为2 571bp,编码856个氨基酸,推测PhTPS6蛋白的分子式为C4342H6838N1154O1276S48。利用实时荧光定量PCR分析PhTPS6在不同组织、不同处理下的表达特性。结果显示:PhTPS6基因在叶腋中表达量较高,而在叶片中的表达量最低;去顶6h引起PhTPS6的表达量升高至对照的14倍,24h后表达量显著下降。而去顶后施加生长素则抑制去顶对PhTPS6的调控。施加细胞分裂素6h后PhTPS6的表达水平显著上调至对照的16倍,随着处理时间的增加,其表达水平逐渐下降。低温处理12h以及盐胁迫处理12h导致PhTPS6表达量分别上调至对照的18.9倍和21.4倍,且随着时间的增加表达量持续上升。该研究表明PhTPS6在矮牵牛分枝发育及低温和盐胁迫中均具有重要作用。     

成都平原西缘笋用竹病虫害种类与分布

为了查明笋用竹病虫害种类及分布危害,为保障笋用竹产业发展和产品安全提供基础信息,采用踏查和标准地调查结合,并辅以灯诱的方法,对成都市主要笋用竹基地以及部分景区和社区竹林地病虫害开展了全面调查。结果显示,成都市笋用竹病虫害共45种,其中害虫38种,病害7种;对危害面积较大的病虫害分布和危害情况进行了分析,提出成都市笋用竹病虫害防控建议。     

马齿形玉米种子尖端激光定向与胚面识别装置研制

为了实现玉米种子的尖端定向与胚面识别,该文以现有尖端定向装置输出的马齿型玉米种子为对象,基于激光开关和测距原理,提出了一种尖端定向与胚面识别方法:依据马齿形玉米种子尖端窄大头宽的轮廓特征,利用激光开关传感器等部件对玉米种子的尖端朝向进行识别,并将大头朝前的玉米种子进行剔除;依据马齿形玉米种子胚面上有胚沟而反面较为平整的表面特征,利用激光测距传感器等部件对尖端朝前的玉米种子进行胚面识别。设计并搭建了玉米种子尖端定向与胚面识别装置,配合现有的尖端定向装置进行试验,结果表明:尖端定向与胚面识别装置的尖端定向成功率达到99.1%,相比现有的尖端定向装置提升了9.5个百分点,胚面识别准确率为96.4%。该方法基本可以实现玉米种子的尖端定向,同时保证胚面识别准确率达到较高水准。该文提出的玉米种子尖端定向与胚面识别方法可为后续玉米种子的自动化定向包装提供参考。     

Methods to improve the fertility of poinsettia

‘Success’ or ‘Red Splendor’ plants propagated by shoot tip culture or embryogenesis had higher pollen germination than those propagated by cutting. All clones of ‘Pepride’, ‘Peter Star’ and ‘Nobel Star’ propagated by cutting or by embryogenesis or shoot tip culture did not have viable pollen. ‘Peter Star’ mutants through mutagenesis could recover pollen viability. When both parents were propagated by tissue culture, fruit set increased compared to when one or both parents were propagated by cuttings. Furthermore, the number of the harvested seeds doubled per pollination set, when the tissue culture parents were used instead of cutting-propagation plants.     

麻江红蒜茎尖组织培养及快繁技术研究

采用正交试验设计方法研究了不同培养基、激素配比对麻江红蒜不定芽诱导、增殖、生根的影响。研究结果表明,B5为适宜的基础培养基;不定芽诱导的适宜培养基为B5 6-BA3.0mg/L NAA0.1mg/L;不定芽增殖的适宜培养基为B5 6-BA0.3mg/L NAA0.1mg/L;适宜的生根培养基为B5 6-BA0.01mg/L NAA0.10mg/L。     

不同继代培养次数对苹果八棱海棠离体培养和遗传转化的影响

以苹果八棱海棠离体新梢和幼叶为外植体,研究不同继代次数对其离体繁殖、再生和遗传转化的影响。结果表明,随着继代培养次数的增加,继代10次和48次的八棱海棠离体增殖倍数、生根能力、不定芽的再生频率、每外植体再生芽数和GUS基因瞬时表达率均显著高于继代5次的;继代10次的增殖倍数和GUS阳性率明显多于继代48次的,其它指标相互间差异不显著;说明继代10次的芽苗较适合用于八棱海棠离体培养的外殖体材料,其幼叶较适于遗传转化研究。