粉花长寿花试管花卉研究

以粉花长寿花茎段为材料,在培养基MS+ BA 1.0 mg/L+ NAA 0.1 mg/L中快速繁育,在1/2 MS+NAA 0.2 mg/L培养基中进行生根培养,获得无菌苗.20 d后在16℃、光周期8 h/d的条件下培养,60 d后花芽诱导率达45％,90 d后达100％;而在22℃、光周期12 h/d和22℃、光周期8 h/d条件下培养,长寿花不形成花芽.将带有花芽的茎段接种在分别添加柠檬黄(0.2 g/L)、葡萄紫(0.2g/L)、苹果绿(25 g/L)和胭脂红(0.4 g/L)的培养基MS+ NAA 0.2 mg/L中,获得4种彩色长寿花“迷你试管花卉”.试验表明:容积为250 mL和500 mL的培养容器观赏时间分别为180 d和300 d.     

Phytophthora nicotianae transmission and growth of potted kalanchoe in two recirculating subirrigation systems

Recirculating subirrigation systems are frequently exposed to the risk of plant pathogens transmission, which may deteriorate the growth and quality of the plants. The transmission of Phytophthora nicotianae was examined using Kalanchoe blossfeldiana cv. New Alter in two recirculating subirrigation systems, a nutrient-flow wick culture (NFW) system and an ebb and flow (EBB) system. When the nutrient solution was infested, the pathogen was recovered from roots in both subirrigation systems. However, foliar blights and browning of roots appeared 4 and 7 weeks, respectively, after inoculation in the EBB system. Only a little discoloration appeared in the NFW system. The fresh and dry weights were lower in the EBB system than in the NFW system. When growing medium was inoculated, the pathogen was unable to be isolated from the plants in the NFW system. However, disease symptoms appeared in the EBB system 4 weeks after inoculation, and the pathogen was observed in the basal leaves and roots. Similar to the infested nutrient solution, the plant growth in the EBB system was inhibited. These results suggested that when the nutrient solution was infested, pathogen transmission could occur in plants in both systems, although differences existed with regard to disease symptoms and the time it took for symptoms to appear. However, we observed that when growing medium was inoculated the pathogen was not transmitted to adjacent plants in the NFW system using wick.     

长寿花叶片的组织培养与快速繁殖研究

选用长寿花叶片作为外植体,在附加有不同激素(细胞分裂素6-BA和生长素NAA)的MS培养基上进行培养,研究激素对长寿花叶片愈伤组织和不定芽增殖的影响.结果表明:不同浓度和种类的激素对长寿花愈伤组织及不定芽增殖的影响不同,最适宜的培养基为:MS 6-BA 2 mg/L NAA 0.3 mg/L.     

橙花长寿花叶柄组织培养技术研究

以橙花长寿花叶柄作为外植体,对其进行不定芽诱导及增殖培养研究,结果表明:最适宜叶柄分化的培养基为MS+6-BA0.5mg/L+NAA2.0mg/L,最适合芽增殖的培养基为MS+6-BA0.5mg/L+NAA0.4mg/L,生根培养基为1/2MS+IBA0.2mg/L,试管苗移栽基质中成活率达98%。     

蔓生吊钟海棠的快繁体系

本试验采用蔓生吊钟海棠幼嫩的叶片和顶芽以及带侧芽的茎切段作为外植体,进行离体培养,筛选出愈伤组织诱导培养基MS+BA 2.0mg/L+NAA 0.2mg/L;胚状体诱导培养基为MS;继代培养基为MS+BA 2.0mg/L+NAA0.2mg/L;微型扦插培养基为MS+BA 2.0mg/L+IAA 0.1mg/L(BA和KT循环使用);壮苗生根培养基为1/2MS.培养基中均加蔗糖30g/L,琼脂7g/L,pH值5.8.繁殖周期35～45d,年增殖率可达2×101 2以上.     

4个品种长寿花试管苗的增殖与生根培养

以4个不同花色长寿花品种的无菌芽苗为材料,比较其试管苗增殖和生根的品种差异。结果表明:在芽苗增殖率、玻璃化程度以及生根率方面,品种之间存在着不同程度的差异。丛生芽诱导的最佳培养基分别是:白花品种,MS NAA0.25mg/L BA1.5mg/L;黄花和红带黄品种,MS NAA0.25mg/L BA0.5mg/L;红花品种,MS NAA0.25mg/L BA1.0mg/L。黄花品种和白花品种的玻璃化程度明显高于红花品种和红带黄花品种。在1/2MS IBA0.1mg/L培养基中获得了较高的生根率,但不同品种间其生根率和生根数有所不同。     

土壤逐渐干旱过程中长寿花叶片生理指标的动态变化

为探讨在土壤逐渐干旱胁迫过程中,长寿花生理生化特性与抗旱性的关系,选取相对含水量、膜透性、可溶性糖和脯氨酸4项指标,研究了其动态变化规律.结果表明土壤干旱胁迫下,与对照相比,相对含水量下降,膜透性、可溶性糖和脯氨酸上升.     

Light integral as an indicator of water use in commercial greenhouse nurseries

Abstract

Irrigation strategies in pot plants of Kalanchoë blossfeldiana were studied in two commercial greenhouse nurseries by continuous weighing of plants on a high-precision balance. The objectives were to study actual irrigation strategies implemented by growers and to evaluate the method of continuous weighing as a potential tool for future irrigation management. Mean values of temperature, relative humidity, light, and weight were recorded every five minutes using data loggers. The change in weight over time was estimated and related to the calculated total canopy surface area of the studied plants. The rate of weight change was then statistically tested in relation to the recorded external factors. The factor with the strongest effect on total water-consumption rate over time was the light integral. As expected, water consumption was also affected by temperature and humidity, as well as the time of day. Although the growers indicated clear irrigation strategies, the study showed that these were not implemented in a true sense or correlated to the information available in greenhouse climate computers. The study also indicated that a high-precision weighing balance might be an important tool for future control of plant growth and plant architecture through irrigation in the pot plant industry.     

<Emphasis Type="Italic">Pythium</Emphasis> and <Emphasis Type="Italic">Phytophthora</Emphasis> species associated with root and stem rots of kalanchoe

Pythium and Phytophthora species were isolated from kalanchoe plants with root and stem rots. Phytophthora isolates were identified as Phytophthora nicotianae on the basis of morphological characteristics and restriction fragment length polymorphism (RFLP) analysis of the rDNA-internal transcribed spacer regions. Similarly, the Pythium isolates were identified as Pythium myriotylum and Pythium helicoides. In pathogenicity tests, isolates of the three species caused root and stem rots. Disease severity caused by the Pythium spp. and Ph. nicotianae was the greatest at 35°–40°C and 30°–40°C, respectively. Ph. nicotianae induced stem rot at two different relative humidities (60% and >95%) at 30°C. P. myriotylum and P. helicoides caused root and stem rots at high humidity (>95%), but only root rot at low humidity (60%).     

Isolation and Characterization of a New Virulence Gene (abvA) of Agrobacterium tumefaciens

A mutant (M-1) was isolated by transposon (Tn5) insertion mutagenesis of Agrobacterium tumefaciens (strain A-208, C58 chromosome, nopaline type T37 pTi, virulent). The M-1 mutant exhibited a complete avirulent phenotype on Kalanchoe daigremontiana leaf and Kalanchoe pinnata stem but a very attenuated virulent phenotype on root of Daucus carota. The mutant had one insertion of Tn5 in pTi. A wild-type target segment (2.3 kb) that included the site of Tn5 insertion in M-1 mutant was cloned. Introducing the 2.3 kb segment into M-1 complemented completely the avirulent phenotype, producing galls as big as strain A-208. The 2.3 kb segment was sequenced, identifying three open reading frames, ORF 1 (354 bp), ORF 2 (261 bp) and ORF 3 (801 bp) in the segment. A Tn5 was inserted between the third and fourth nucleotide of ORF 1 in M-1. The ORF 1 had no homology to any reported genes and thus was named the abvA gene. The ORF 3 had the high homology (identities 44%, positive 68%) to the gene of the sarcosine oxidase β subunit (accession no. sp/P40875). Introduction of the DNA segment (743 bp) containing the abvA gene and its promoter region into M-1 partially complemented the avirulent phenotype of the mutant, producing galls smaller than strain A-208. The abvA gene was distributed not only on nopaline-type pTi (T37) but also on octopine-type pTi (A6NC) and chromosome (C58) of A. tumefaciens. M-1, being avirulent on K. daigremontiana and K. pinnata, had a Tn5 insertion only in the abvA gene on pTi but not in the abvA gene on the chromosome, implying that the abvA gene on the chromosome in strain A-208 is not functional. A binary vector, pIG121-Hm, containing the β -glucuronidase (GUS) gene with an intron was introduced into M-1, which was then applied to leaves of K. daigremontiana to assay GUS activity for monitoring T-DNA transfer to the host nucleus. High GUS activity comparable to that in strain A-208 was detected in M-1 in spite of its inability to induce galls, suggesting that M-1 can transfer T-DNA into the host nucleus, but cannot integrate it into the chromosome. Received 25 October 2000/ Accepted in revised form 28 December 2000