以根为外植体建立大蒜的组织培养体系

以国内4个大蒜栽培品种为材料,建立了以根为外植体的再生体系。将蒜瓣去皮后灭菌消毒,萌发后选取苗龄为5~7 d的无菌苗的根接种到含不同激素配比的培养基中进行愈伤组织诱导,发现MS+2,4-D 1 mg/L+2ip 0.1 mg/L组合愈伤诱导效率最高,平均为56.06%;愈伤组织经过2~3次继代培养,选取胚性愈伤组织置于不同分化培养基上进行培养,2~3个月后可见小芽产生,分化培养基为MS+KT 1 mg/L时,植株再生效率最高,平均达到35.01 %。本研究建立了一种以根为外植体的高效的大蒜愈伤诱导和再生体系,为大蒜遗传转化体系的建立打下良好基础。     

Effects of tissue culture conditions and explant characteristics on direct somatic embryogenesis in Oncidium `Gower Ramsey'

The effects of tissue culture conditions and explant characteristics on direct somatic embryogenesis were studied on Oncidium `Gower Ramsey'. Embryo formation was significantly affected by explant position. Leaf tip segments had a significantly higher embryogenic response than other segments of leaves. Adaxial-side-up orientation significantly promoted embryogenesis in comparison with abaxial-side-up orientation. There was no significant effect of sucrose in a range of concentrations (10–60 g l^–1). Modified 1/2-MS medium (containing 85 mg l^–1 KH₂PO₄) supplemented with 170 mg l^–1 NaH₂PO₄ significantly promoted direct somatic embryogenesis. Peptone at 0.5 mg l^–1 gave significantly higher emrbyogenic response (80%) on leaf tips than control treatment (50%). The best response on direct embryo formation was obtained on the modified 1/2-MS medium supplemented with 10–20 g l^–1 sucrose, 170 mg l^–1 NaH₂PO₄ and 0.5 g l^–1 peptone.     

影响一品红再生系统建立的因素

本试验以一品红“旗帜”和“福星”两个品种的茎段和叶片为试验材料,研究了影响建立一品红再生系统的因素。筛选出一品红初代培养的适宜培养基。     

Micropropagation of <Emphasis Type="Italic">Terminalia bellirica</Emphasis> Roxb.—A sericulture and medicinal plant

Summary A protocol for micropropagation of plants via axillary bud proliferation from nodal explants of Terminalia bellirica Roxb. seedlings has been established. Explants were cultured on Murashige and Skoog medium with different concentrations of 6-benzyladenine (BA; 4.4, 8.9, 13.3, 17.8, or 22.2 μM) or kinetin (Kn; 4.6, 9.3. 14.0, 18.6, or 23.2 μM). Within the range evaluated, the medium containing 13.3 μM BA showed the highest shoot length (1.9=0.2 cm) in the primary culture. When separated and transferred to fresh subculture medium with lower levels of BA (2.2. 4.4, 6.6, or 8.9 μM) or Kn (2.3, 4.6, 6.9, or 9.3 μM), the nodal segments from individual regenerants (obtained initially from seedling nodes) showed efficient shoot induction at 4.4 μM BA. Rooting of the shoots was achieved under in vitro conditions on two media tested, i.e., modified Gamborg's (B₅) medium or Woody Plant Medium, both supplemented with 4.9 μM indole-3-butyric acid. Regenerated plants were established in the greenhouse.     

Changes in the accumulation of flavonoid and isoflavonoid conjugates associated with plant age and nodulation in alfalfa (Medicago sativa)

Carbohydrate and mineral nutrition was studied in relation to abscission in fruitlets from leafy inflorescences of the Washington navel orange ( Citrus sinensis [L.] Osbeck). Differences in the growth rate of the fruitlets permitted to predict abscission several weeks in advance. This allowed characterization of early differences in composition and behaviour of persisting and abscising fruitlets.
Inflorescences with persisting fruitlets accumulated more mineral elements than inflorescences with abscising fruitlets, and for the phloem-mobile elements the excess accumulation was allocated to the fruitlets. Starch accumulated in the inflorescence leaves during early fruitlet growth, and this accumulation was enhanced by the persisting fruitlets despite their higher growth rate and mobilizing ability. The relations between the fruitlets and the inflorescence leaves cannot be explained totally in terms of source sink relationships; a hormonal regulation of the leaves by the fruitlets is postulated.
Acid invertase activities and hexose concentration in the pericarp were higher in the abscising fruitlets. The lower early growth rate of these fruitlets is thus not caused by a limitation in carbohydrate supply. It seems more related to carbohydrate utilization, probably hormonally mediated, as demonstrated by the higher dependence on hormone supply for the growth in vitro of the endocarp explants.     

A rapid and efficient method for regeneration of plantlets from embryo explants of cumin (Cuminum cyminum)

A new, simple and efficient method was developed for multiple shoot regeneration of cumin from imbibed embryo cultures. This method yielded a large number of shoots within short period of time (30–50 days) without any subculturing. The effects of different media, different embryo explants and various combinations of plant growth regulators (PGRs) on callus formation and shoot regeneration in cumin were investigated. Simultaneous callus formation and shoot regeneration was obtained. The best response for multiple shoot regeneration was observed on B5 medium containing 1.0 mg l^–1 BAP, 0.2 mg l^–1 NAA and 0.4 mg l^–1 IAA, with an average of 140 shoots per explant.     

Rapid clonal propagation of guava through in vitro shoot proliferation on nodal explants of mature trees

In vitro clonal propagation of guava Banaras local was achieved by culturing nodal explants of mature trees on Murashige and Skoog (MS) revised medium supplemented with 4.5 M 6-benzyladanine (BA) alone or in combination with either 0.6 M indole-3-acetic acid (IAA), 0.5 M indole-3-butyric acid (IBA) or 0.3 M gibberellic acid (GA₃). Multiple shoots were induced to form by enhancement of axillary branching and BA (4.5 M) without any auxin and gibberellin was found to give best shoot multiplication rate. In this medium 3–6 shoots developed on explants collected from field-grown plants and 5–10 shoots developed on explants taken from in vitro proliferated shoots within 12 wk of culture. A prior transfer of shoot clumps to a medium containing a lower concentration of BA (0.5 M) before harvesting of cuttings for rooting allowed rapid extension growth and increased the number of usable shoots per culture. Adventitious rooting occurred after subculturing excised shoots on a medium containing 1/2 strength MS salts, 1.5% sucrose, 1 M each of IBA and -naphtha-leneacetic acid (NAA), and 1 gl^-1 activated charcoal. Regenerated plantlets were successfully established on soil.     

Effects of growth regulator concentrations and explant size on shoot organogenesis from callus derived from zygotic embryos of sunflower (Helianthus annuus L.)

Effects of medium growth regulator composition and embryo size on shoot organogenesis of callus derived from globular- to torpedo-shaped zygotic embryos of five sunflower (Helianthus annuus L.) genotypes were examined. Forty growth regulator combinations composed of 0 to 5 mgl^-1 naphthaleneacetic acid (NAA) and 0 to 1 mgl^-1 6-benzylaminopurine (BA) were tested. The frequency of zygotic embryos forming shoot-regenerating callus was analysed according to categorical data modelling using a maximum-likelihood approach. Both NAA and BA must be present to induce the formation of morphogenic callus from zygotic embryos, but each growth regulator effect varied with the genotype. For four genotypes, NAA and BA effects were neither linear nor quadratic; whereas, they were linear for the fifth one. Most effective concentrations across genotypes were 0.1 mgl^-1 NAA and 0.5 mgl^-1 or 0.2 mgl^-1 BA. However, the optimal growth regulator combination depended on the genotype and an interaction between the two growth regulators. The frequency of shoot-regenerating callus also varied with the size of the embryo explant. For all five genotypes, 0.4 to 1.2 mm long heart-shaped zygotic embryos formed morphogenic callus more frequently than smaller less-developed ones.     

Shoot regeneration from adventitious buds induced on juvenile and adult almond (Prunus dulcis mill.) explants

Summary Adventitious shoot regeneration was achieved from almond leaves, cv. Boa Casta, excised fromin vitro cultures of juvenile and adult material. Murashige and Skoog (1962) medium (MS) was found to be more efficient for adventitious shoot induction than a modified medium of Quoirin et al. (1977) when using identical growth regulator supplements. Thidiazuron (TDZ) at 4.54, 5.90, 6.81, and 9.08 μM was used in all induction media, together with indole-3-butyric acid (IBA), indole-3-acetic acid (IAA), or a combination of IAA and 2,4-dichlorophenoxyacetic acid (2,4-D). When N⁶-benzyladenine (BA) was used instead of TDZ, no adventitious shoots were induced. Leaf explants of juvenile origin yielded the highest regeneration rates (40.0 and 38.2%) and required higher concentrations of TDZ for shoot induction than leaves of adult origin. An increase from 15.0 to 35.3% in the regeneration ability of adult leaf explants, tested on one of the induction media, modified medium of Quoirin et al. (1977) supplemented with 5.90 μM TDZ and 2.85 μM IAA], was achieved when donor shoots were subcultured twice on a medium with a low BA concentration of 1.33 μM.     

Growth and development of Citrus pistils and fruit explants in vitro

Pistils and various fruit explants of Citrus limon L. Burm. f. and Citrus sinensis L. Osbeck were cultivated in vitro . Basal medium as well as medium supplemented with IAA, GA₃ or benzylaminopurine, supported growth of all explants for more than one year. Pistils did not enlarge considerably, but gave rise to active callus growth; callus proliferation and viability was enhanced by all hormones. Culture of fruit slice explants resulted, in addition to peel hypertrophy and callus proliferation, in a marked growth of two distinct types of juice vesicles. The growth of juice vesicle explants was promoted by all three growth hormones. – It is suggested that the successfully prolonged in vitro culture of various fruit explants, and especially of juice vesicles, may aid in studies of fruit development and physiology.