红芽芋球茎片两步法离体快繁及其再生苗生理和光合特性研究

以江西铅山红芽芋(Colocasia esculenta L.Schott var.cormosus‘Hongyayu’)试管苗为材料,建立了芋球茎片两步法离体快繁体系,并对其再生苗的形态指标、染色体数目、生理和光合特性以及叶绿素荧光特性进行了检测。结果表明:(1)红芽芋球茎片单芽诱导的最佳培养基为MS+KT 2 mg/L+6-BA 1 mg/L+NAA0.1mg/L,诱导培养30d后将单芽从球茎片上分离,再接种到生根培养基(MS+KT 2mg/L+NAA 0.1mg/L)上培养30d即可形成完整植株,移栽成活率高达98%;(2)由球茎片单芽、丛生芽、不定芽离体快繁获得的红芽芋再生苗在形态指标、叶下表皮气孔参数、染色体数目、生理生化指标以及叶片光合特性参数和叶绿素荧光特性方面均无显著差异。说明红芽芋球茎片两步法离体培养的再生苗繁殖系数高、染色体数目稳定,该离体快繁体系可应用于江西铅山红芽芋的工厂化生产。     

Changes in Phenolics, Polyphenol Oxidase and its Isoenzyme Patterns in Relation to Resistance in Taro against Phytophthora colocasiae

The effect of Phytophthora leaf blight disease, caused by Phytophthora colocasiae Raciborski, on the accumulation of phenolics and polyphenol oxidase (PPO) activity in ex vitro plants was studied in three resistant (DP‐25, Duradim and Jhankri) and one susceptible (N‐118) genotypes of taro [Colocasia esculenta (L). Schott]. The inoculation of taro leaves with P. colocasiae spores resulted in a quantitative change in both biochemical parameters and induction of PPO isoforms in resistant genotypes. The amount of phenolics was increased owing to blight by 68.02%, 58.87%, 52.67% and 11.50% in DP‐25, Duradim, Jhankri and N‐118, respectively. The per cent increase in PPO under stress over non‐stress condition was also highest in DP‐25 (49.14%) followed by Duradim (41.56%), Jhankri (40.55%) and N‐118 (17.08%). The resistant genotypes showed higher activity of PPO as compared with susceptible ones, which was reflected through its banding pattern in isoenzyme analysis, detecting four different isoforms. The intensity of the bands was higher in the resistant genotypes than in susceptible N‐118. The appearance of high intensity bands and/or reduction in the intensity of particular isoform(s) in the zymograms of all the three resistant taro genotypes studied, led to the apparent conclusion of linking PPO isoenzyme expression with blight resistance in taro. The blight incidence (per cent leaf infection and leaf area infection) was lower in the resistant genotypes than in susceptible, N‐118. The yield reduction owing to blight was below 20% in DP‐25, Jhankri and Duradim, while the same was more than 40% in N‐118. The phenolics and PPO activity was negatively correlated with disease incidence and yield reduction owing to blight. Based on the results of disease incidence, biochemical contents and yield, the pattern of stress tolerance was DP‐25 > Duradim > Jhankri > N‐118. The studied parameters, i.e. phenolics and PPO could be used as biochemical markers for leaf blight stress tolerance studies in taro.     

江西铅山红芽芋脱毒苗球茎愈伤组织诱导及其再生体系的建立

以江西铅山红芽芋脱毒苗为试材,研究不同因素对红芽芋脱毒苗球茎愈伤组织诱导及其再生体系的影响,以期对红芽芋脱毒苗的再生体系进行优化。结果表明,红芽芋脱毒苗球茎愈伤组织诱导的最佳培养基是MS+TDZ 2 mg·L^-1+2,4-D 1 mg·L^-1。红芽芋脱毒苗球茎愈伤组织分化的最佳培养基是MS+TDZ 2 mg·L^-1+NAA 1 mg·L^-1。红芽芋脱毒苗不定芽生根的最佳培养基是1/2MS+NAA 0.5 mg·L^-1+PP₃₃₃ 0.5 mg·L^-1。红芽芋再生苗最好的移栽基质为发酵后的腐锯木屑。红芽芋脱毒苗球茎愈伤组织再生苗移栽时最佳的PP₃₃₃浓度为20～50 mg·L^-1。本试验成功建立了红芽芋脱毒苗球茎愈伤组织的再生体系,为红芽芋脱毒苗转基因的研究和种质创新奠定了基础。     

烟草和香芋上斜纹夜蛾的自然种群生命表

应用作用因子生命表方法,组建烟草和香芋上第2、3代斜纹夜蛾Spodoptera litura（Fabricius）自然种群生命表,分析作用因子对斜纹夜蛾种群数量的控制作用。结果表明,2005和2006年烟草和香芋上第2、3代斜纹夜蛾种群的增长倍数均以香芋高于烟草。无论烟草还是香芋上第2、3代斜纹夜蛾,均以“捕食及其它”的排除作用控制指数最大。如排除所有天敌等作用因子的作用,2005年烟草上第2、3代斜纹夜蛾自然种群趋势指数将分别增长31．2029和50．0371倍,香芋上第2、3代斜纹夜蛾自然种群趋势指数将分别增长29．3492和41．2873倍;2006年烟草上第2、3代斜纹夜蛾自然种群趋势指数将分别增长33．1421和75．4167倍,香芋上第2、3代斜纹夜蛾自然种群趋势指数将分别增长31．5357和70．5355倍。说明天敌等自然作用因子对斜纹夜蛾种群数量有较为明显的控制作用,而烟草上的自然作用因子的作用要强于香芋上的自然作用因子。     

Plant regeneration in vitro of South Pacific taro (Colocasia esculenta var. esculenta cv. Akalomamale,Aracea)

Summary Axillary bud expiants from South Pacific (Solomon Islands) taro, Colocasia esculenta var. esculenta cv. Akalomamale (Araceae) cultured on a modified Murashige-Skoog medium containing 1 mg NAA 1^–1 and TE formed callus and produced multiple plantlets. Explants died if NAA was present at levels lower than 0.1 mg 1^–1. BA was not required and may have been inhibitory. Plantlets developed faster and became larger following transfer to a hormone-free medium two weeks after the start of culture. Fully grown plants were established in a potting mix and are growing well in a greenhouse.Abbreviations BA benzyladenine - BM basal medium - Ca Colocasia esculenta var. antiquorum - Ce Colocasia esculenta var. esculenta - Ck cytokinin(s) - CW coconut water - HSMSM half strength Murashige Skoog macroelements - HSMS half strength Murashige and Skoog medium - IM initial medium(ia) - MS Murashige and Skoog medium - NAA naphthaleneacetic acid - SM second medium - TE taro corm extract - UCI University of California, Irvine     

芋侧球茎发生发育的形态学机理

观察了魁芋和多子芋腋芽、侧球茎发生发育的形态学变化规律,分析了主球茎顶芽和不同发育期腋芽中蛋白质的组成。结果表明,魁芋每一叶轮上腋芽数目为１;多子芋为３或３个以上,其中一个体积较大。魁芋侧球茎发育初期伸长的速度大于增粗,首先形成圆柱型,然后顶端膨大形成体积很小的侧球茎。多子芽腋芽伸的同时茎部明显变粗,首先形成圆锥型,然后发育成品种特有的形状。根据发育进程将腋芽发育分成ＡＢ１－ＡＢ９个时期,将主球茎     

芋对斜纹夜蛾的诱集作用

用 4个芋头品种在菜田进行斜纹夜蛾 (SpodopteralituraFabricius.)诱集试验 ,结果表明 ,香梗芋和槟榔芋诱集虫卵、幼虫效果最好 ,其它芋品种亦有一定的诱集效果 ;芋头与其它蔬菜种植面积比例为 1∶9、1∶3和 1∶1时 ,以 1∶9的综合防治效果最佳。     

The taro monoculture of central New Guinea

An ancient, sustainable, and low risk Colocasiataro monoculture has persisted until modern times among the Mountain Ok peoples of central New Guinea. There is a monoculture-polyculture axis in the region with taro monocultures predominant in the rain forests of the mid-altitude fringe. We argue that when examined from the standpoint of ecosystem simplification, biological variability, and subsistence vulnerability, the taro monocultures exhibit many ecological and systemic properties commonly attributed to polycultures. Monoculture is not an exclusive category; specific cases must be placed in a broader context of the larger ecosystem and the options people have at their disposal. Reduction of the taro monoculture is occurring in response to modernization pressures.