白玉龙火龙果不同外植体的离体培养

【目的】研究白玉龙火龙果子叶、下胚轴及子叶节的不定芽诱导及茎段增殖技术,为白玉龙火龙果的品种改良及快繁育苗提供技术支持。【方法】以白玉龙火龙果种子培育的无菌苗为材料,采用正交试验设计分析不同培养基、不同植物生长调节剂与浓度及其组合对白玉龙火龙果子叶、下胚轴及子叶节不定芽诱导及茎段增殖与生根的影响。【结果】白玉龙火龙果子叶、下胚轴及子叶节均能直接诱导不定芽发生。其中,16个正交处理均能诱导子叶节不定芽发生,其最优诱导培养基为WPM+0.50 mg/L TDZ+0.50 mg/L CPPU+0.05 mg/L 6-BA+1.0 mg/L NAA,诱导率为87.1%~100.0%;子叶仅1个处理未能诱导出不定芽,最高诱导率为36.0%,其最优诱导培养基为1/2MS+0.50 mg/L TDZ+0.05mg/L CPPU+2.00 mg/L 6-BA+0 mg/L NAA;下胚轴仅5个处理能诱导出不定芽,最高诱导率仅3.0%,其最优诱导培养基为1/2MS+0.05 mg/L TDZ+2.00 mg/L CPPU+1.00 mg/L 6-BA+1.0 mg/L NAA。茎段去顶处理有利于腋芽的诱导萌发,去顶处理的最大增殖系数为4.2,不去顶处理的最大增殖系数为3.1,其最优增殖培养基为WPM+0.50 mg/L 6-BA+0.05 mg/L IBA。NAA处理能促进茎段生根,适宜的生根培养基为1/2MS+0.1~0.5 mg/L NAA,生根率达100.0%。【结论】不同基本培养基、植物生长调节剂与浓度及其组合均能诱导白玉龙火龙果子叶、下胚轴和子叶节不定芽发生及茎段芽增殖和不定根产生。其中,不定芽诱导以子叶节最易诱导发生,其次为子叶,下胚轴较难;茎段芽增殖和不定根诱导均较容易。     

Binucleate Rhizoctonia (Ceratorhiza spp.) as non-mycorrhizal endophytes alter Pinus sylvestris L. seedling root architecture and affect growth of rooted cuttings

The main aim of this study was to assess critically the effects of binucleate Rhizoctonia (BnR) inoculation on Scots pine (Pinus sylvestris L.) seedling and hypocotyl root architecture and early plant growth in tree seedling nursery soil, Sphagnum peat and forest humus. The BnR isolates (251, 266, 268, 269) stimulated early seedling growth in the nitrogen-limited nursery soil 86 days postinoculation (p.i.). These seedlings exhibited significantly higher root length and reduced root width, although percentage root infection levels were <6%. At a harvest 240 days p.i., no significant plant and root growth differences were identified, although short root numbers were significantly increased. BnR infection detected in roots was characterized by the presence of intercellular fungal hyphae and subtending intracellular monilioid fungal cells located in outer cortical cells of long roots. Similar endophytic infection morphology was detected in adventitious roots generated in prerooted hypocotyl cuttings [Kaparakis, G. & Sen, R. (2006). Scandinavian Journal of Forest Research, 21] exposed to all BnR isolates in nursery peat and forest humus, although isolate-specific cutting growth was detected. In conclusion, these BnR isolates, known to be genetically related to orchid mycorrhizal Ceratorhiza spp., are non-pathogenic and have the capacity to stimulate significantly early Scots pine root development in nursery soils and forest humus.     

有翅孤雌型桃蚜口器感受器的扫描电镜观察

采用扫描电镜技术对有翅孤雌型桃蚜口器上的感受器进行了系统的观察与分析。结果表明:感受器大都集中于喙管表面,主要有毛形感受器、刺形感受器及锥形感受器三种类型。其中,毛形感受器和刺形感受器分布于整个喙管的表面;锥形感受器只存在于喙管的顶端,共16根且以口沟为中心对称分布。笔者分别描述了三种感受器的外部形态特征,并对其可能的功能进行了初步探讨。     

红树植物秋茄造林技术的研究

据物候观测，秋茄最佳采种（胚轴）在海南（琼山）为２月上旬至３月初，廉江在２月下旬至４月底，深圳为３月上旬至５月初；采用胚轴插植方法造林并在淤泥松软、风浪大的滩涂适当深栽（２／３种苗长度），半年成活率达８８％，用１至多年生小苗或幼树造林，半年成活率小于３７％；潮浸深度对幼苗和幼树生长影响极大，选择和规划造林地时，首先应确定宜林滩涂潮汐基面高程，该高程因各地潮汐特点不同而异，深圳湾应大于１．３ｍ；造林初植密度以０．５ｍ×１ｍ或１ｍ×１ｍ适当密植为宜。     

菘蓝子叶和下胚轴组织培养再生植株的研究

以菘蓝子叶和下胚轴为外植体进行组织培养，筛选出植株再生的适宜的培养基为ＭＳ＋ＫＴ２ｍｇ／Ｌ＋ＮＡＡ０．２ｍｇ／Ｌ。对器官发生进行系统的细胞组织学观察发现：菘蓝下胚轴培养，细胞启动和不定芽的形成随下胚轴部位的不同而有所不同；不定芽发生的数量与其维管轴的发育有关，整个下胚轴分化不定芽的数量呈梯度变化。     

油菜下胚轴再生频率影响因素研究

以甘蓝型油菜Brassica napus双低品种湘油13号为材料,对其下胚轴再生频率影响因素诸如种子萌发培养基、外植体、基本培养基、激素、愈伤组织龄期和AgNO3浓度等进行了研究。结果表明,在种子萌发培养基中加入适量激素,种苗质量好,其下胚轴愈伤组织发生早,形成快,诱导频率高,选取4d苗龄的种苗下胚轴靠近根基部或近子叶端0.3～0.5cm长为针植体,能使愈伤组织发生早,形成快,诱导频率也高,以B5 2,4-D0.3mg/L 6-BA3mg/L为诱导培养基,MS 6-BA3mg/L GA30.5mg/L为分化培养基,最终诱导频率高,在分化培养基中再加入适量AgNO3,芽苗分化频率成倍提高,以加入20umol/LAgNO3分化频率最高,选取16d的愈伤组织,分化效果较好。     

Plant Regeneration from Hypocotyl Protoplast of Brassica campestris

以大白菜成青２号为材料,从萌发５天的无菌苗下胚轴分离原生质体,然后以附加８．２％葡萄糖,０．４ｍｇ／Ｌ２,４－Ｄ,０．４ｍｇ／ＬＮＡＡ和０．５ｍｇ／Ｌ６－ＢＡ的改良ＫＭ８ｐ液体培养基进行浅层培养．培养１３天后,用含５．２％葡萄糖的ＫＭ８ｐ培养基以１∶１进行稀释．４～６周后,再生细胞分裂并形成愈伤组织,直径约０．４～０．５ｍｍ的愈伤组织经ＭＳ培养基（附加２％蔗糖,０．８％的琼脂,１．５ｍｇ／Ｌ６－ＢＡ,０．５ｍｇ／ＬＮＡＡ和０．２ｍｇ／Ｌ２,４－Ｄ）诱导植株分化．５９％的愈伤组织可分化形成芽,分化的芽经诱导生根发育成完整的植株．０．８ｍｇ／ＬＩＢＡ和４００ｍｇ／Ｌ的羧苄青霉素对分化再生有促进作用．     

决明原生质体的分离与培养研究

用决明（ＣａｓｉａｏｂｔｕｓｉｆｏｌｉａＬ．）子叶和下胚轴为材料,游离和培养原生质体。结果表明,１５日龄无菌苗的子叶和下胚轴比较适于游离原生质体,每１ｇ材料的原生质体产量高达１．６×１０４个;ＰｅｃｔｏｌｙａｓｅＹ－２３是分离原生质体所必需的;用含２,４－Ｄ０．４ｍｇ／Ｌ（以下单位同）,ＮＡＡ１．０与ＫＴ０．１的ＫＭ８Ｐ漂浮培养利于原生质体的分裂。培养４ｄ后,原生质体开始分裂,１５ｄ后其植板率约为１９．２％,３０ｄ形成了细胞团或小愈伤组织。增殖愈伤组织在分化培养基上培养,可分化出芽。芽在生根培养基上培养１４ｄ生根,从而再生决明小植株。     

外源IBA对辣椒下胚轴不定根发生的调控作用

为了探明吲哚丁酸(Indole-3-butyric acid,IBA)对辣椒(Capsicum annuum L.)下胚轴不定根发生的诱导机制,采用IBA浸蘸后扦插的方法,研究了外源IBA处理后辣椒下胚轴不定根发生进程、糖类物质转化与不定根发生相关基因表达情况。结果表明:外源IBA诱导辣椒下胚轴不定根发生具有浓度依存效应,150μmol·L~(-1) IBA处理后不定根发生区段长度、不定根数及平均根长分别是对照的3.47倍、3.28倍和1.91倍;150μmol·L~(-1) IBA上调了不定根启动相关基因Ca ARL1和Ca Cyc B1的表达,下胚轴的不定根原基发生区域明显增加;此外,150μmol·L~(-1) IBA还上调了下胚轴不定根发生区段糖代谢相关基因Ca CWI和Ca STP的表达,可溶性糖、淀粉含量及细胞壁转化酶活性显著提高。结果表明适宜浓度IBA处理可以促进辣椒下胚轴不定根发生区段糖类物质的积累和转化,诱导辣椒下胚轴不定根的发生。     

Influence of soil type and indigenous pathogenic fungi on bean hypocotyl rot caused by Rhizoctonia solani AG4 HGI in Cuba

Calcisol, ferralsol and vertisol soils, representative of different bean production areas of Villa Clara province in Cuba, were selected to determine the impact of soil type on bean hypocotyl rot severity caused by Rhizoctonia solani AG4 HGI (isolate CuVC-Rs7). In inoculated autoclaved soil, hypocotyl rot was most severe in calcisol soil, followed by ferralsol soils and then vertisol soils. In inoculated natural soils, disease severity was lower in vertisol and calcisol soils and higher in ferralsol soil, indicating that biological factors are suppressing or stimulating the pathogenic efficiency of R. solani. Native binucleate Rhizoctonia AGF, Sclerotium rolfsii and R. solani AG 4 HGI were isolated from bean plants grown in natural calcisol, vertisol and ferralsol soils, respectively. Subsequent studies about the interaction between these fungi and R. solani indicated that they were involved in the variability of disease severity caused by R. solani. The addition of R. solani AG4 HGI (isolate CuVC-Rs7) into each autoclaved soil inoculated with binucleate Rhizoctonia or S. rolfsii resulted in a reduction of disease severity caused by this pathogen while in soils inoculated with native R. solani AG4 HGI, disease severity increased. Irrespective of fungal interactions, calcisol was always the most disease conducive soil and vertisol the most disease repressive soil. The mechanisms by which native pathogenic fungi could influence disease severity caused by R. solani are discussed.