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Micropropagation protocol for Diplocyclos palmatus through direct shoot induction from isolated cotyledon and leaf explants was established. Cotyledons were isolated from 2-week-old seedlings and cultured in the Murashige and Skoog (MS) medium supplemented with various concentrations of 6-benzylaminopurine (BAP, 0.5–2.0 mg L−1) alone or in combination with α-naphthalene acetic acid (NAA, 0.2–1.0 mg L−1) for shoot induction. The highest frequency of response (89%) and the mean number of shots (6.8) were observed in an MS medium supplemented with 1.5 mg L−1 BAP and 0.5 mg L−1 NAA. Leaves at various stages of development were isolated from in vitro grown shoots and cultured in an MS medium supplemented with different concentrations of BAP (0.5–2.5 mg L−1), Thidiazuron (TDZ, 0.5–2.5 mg L−1) alone and in combination with NAA (0.2 mg L−1) for shoot induction. The highest shoot induction frequency of 91% and shoot number of 7.8 shoots per explant were observed when 15-d-old- leaves were cultured in an MS medium enriched with 2.0 mg L−1 TDZ and 0.5 mg L−1 NAA after 45 d. The isolated cotyledon and leaf-derived shoots showed optimum rooting on ½ MS medium fortified with 4.0 mg L−1 indole-3-butyric acid (IBA). The rooted plants were transferred to the soil with 90% success. [ABSTRACT FROM AUTHOR]

In vitro propagation of pitcher plants is still limited only using seeds, while the other in vitro methods using leaf explants such as embryogenesis, organogenesis, and callus culture has not been widely reported. The research aims to study the growth response of leaf explants in two species of pitcher plants (Nepenthes gracilis and Nepenthes reinwardtiana), which formed callus in several treatment media combinations. Leaf pieces were taken from a 4-month pitcher plant culture were grown on the treatment media, namely modified media of Murashige & Skoog with a half concentration (½ MS) added 2.4-Dichlorophenoxoxyacetate (2.4-D) with a concentration of 0, 0.5, 1, 1.5, and 2 mg L-1 and kinetin (0.5 mg L-1). The treatment was then stored in a dark environment to induce callus formation. The observation for 12 weeks showed that the time of callus formation in two species of pitcher plant observed was not significantly different. Both species of pitcher plants begin to form callus in the fourth week after treatment. None of the leaf explants were planted on the control medium without hormones formed callus. The best medium for callus induction in N. gracilis is ½ MS medium added with 2 mg L-1 2,4-D and 0.5 mg L-1 kinetin, with callus morphology brownish-white with friable texture. In comparison, the optimum callus media from leaf explant of N. reinwardtiana has not been obtained yet. Thus further research is still needed.

A protocol for plant regeneration via direct induction of protocorm-like bodies (PLBs) from leaf segments of Tolumnia Snow Fairy was developed as a basis for mass production. Ten-month-old, in vitro-grown donor plantlets were obtained by inducing shoots from buds on the flower stalk. Leaf segments harvested from plantlets of different heights and from expanding leaves at different positions were compared, as were two BA concentrations with 0.5 mg·L-1 NAA. The greatest rate of PLB induction (16.7%) was observed when leaf segments taken from 1- to 2-cm height plants were cultured in Murashige and Skoog (MS) basal medium supplemented with 2 mg·L-1 BA and 0.5 mg·L-1 NAA after 16 weeks of culture. When using leaf explants, only inner, expanding leaves cultured on MS basal medium supplemented with 4 mg·L-1 BA and 0.5 mg·L-1 NAA resulted in PLB induction, at an average rate of 25.5 PLBs per explant. After 16 weeks of culture, histological and scanning electron microscopy (SEM) observations revealed that PLBs originated from epidermal cells of leaf explants. PLBs of 1 to ≤2 mm in diameter continued to proliferate after 4 weeks of culture. These secondary PLBs could be produced from either whole PLBs or the upper side of PLBs. Finally, PLBs were regenerated into plantlets. After ≈ 14 months of culture, fully developed plants exhibiting well-developed roots and shoots were acclimatized. These plants grew well, with 1-year survival rates of nearly 73%, for plants originating as explants taken from 1- to 2-cm tall plants, and of 79%, for plants originating as explants taken from inner leaves. Some mature plants flowered 1 year after transplantation. This study presents a simple system that can provide a large number of PLBs for mass propagation in a short time that can be converted into plants and also used for the new cultivars of Tolumnia orchids. [ABSTRACT FROM AUTHOR]

The leaf-explants of Saintpaulia ionantha Wendl. var.'miniature' were treated by different doses of MNH and cultured on shoot regeneration medium. A strong toxic effect of some MNH doses on explant survival during the first two subcultures was noticed. The explants surviving treatment regenerated shoots with the efficiency comparable to the control. The high number of shoots regenerated from mutagenised leaves showed chlorophyll chimerism (so-called variegated forms). The use of 5 mM MNH for 1.5 or 2 h was found very effective, as 100% of survived explants regenerated variegated shoots. Besides hundreds of variegated forms also leaf-shape and flower-colour variants were observed in MNH-treated culture. Somaclonal variation was not observed in the control culture. The results indicate the great efficiency of in vitro applied MNH for in-duction of morphological variants of Saintpaulia, and especially variegated forms.

A tissue culture system was established from young leaves of in vitro grown seedling of Torenia fournieri Lind. Leafsegments were cultured on Murashige and Skoog medium (MS) medium supplemented with combinations of NAA and BA. Shoot organogenesis was observed in all growth regulators containing medium. High frequency regeneration was obtained from leaves cultured on MS medium supplemented with 0.05 mg/l NAA plus 3 mg/l BA. When individual isolated shoots were transferred to MS medium devoid of growth regulators, complete plantlets were obtained. Adventitious shoots were also regenerated from callus that was derived from leaf explants and a high frequency of shoot organogenesis was found on MSmedium containing 0.1 mg/l NAA plus 3 mg/l BA.

[Objective] This research aimed to optimize continuously the highly efficient regeneration system of Anthurium andraeanum. [Method] The leaves and petioles of four A. andraeanum varieties were used as expiants to investigate the differences in primary callus induction among different A. andraeanum varieties. [Result] The callus formation capacity of SAM and SST was stronger than that of SDM and SHG. Among the four varieties, the leaf regeneration capacity of SAM, SDM and SHG was stronger than the corresponding petiole regeneration capacity. However, the petiole regeneration capacity of SST was stronger. The optimum medium for petiole callus induction of SST was 1/2 MS + TDZ 4.0 mg/L + 2, 4-D 0.2 mg/L with induction rate of 87.5%; the optimum medium for leaf callus induction of SAM was 1/2 MS + TDZ 2.0 mg/L + 2, 4-D 0.2 mg/L with induction rate more than 90%; the optimum medium for leaf callus induction of SDM and SHG was all 1/2 MS + ZT 2.0 mg/L + 2, 4-D 0.2 mg/L with induction rates of 59.34% and 79.63%, respectively. [Conclusion] in addition to variety differences, the differences in differentiation ability among different types of calluses should be also taken into account in the establishment arid optimization of tissue culture and rapid propagation technology system of A. andraeanum. [ABSTRACT FROM AUTHOR]

A tissue culture system was established from young leaves of in vitro grown seedling of Torenia fournieri Lind. Leaf segments were cultured on Murashige and Skoog medium (MS) medium supplemented with combinations of NAA and BA. Shoot organogenesis was observed in all growth regulators containing medium. High frequency regeneration was obtained from leaves cultured on MS medium supplemented with 0.05 mg/l NAA plus 3 mg/l BA. When individual isolated shoots were transferred to MS medium devoid of growth regulators, complete plantlets were obtained. Adventitious shoots were also regenerated from callus that was derived from leaf explants and a high frequency of shoot organogenesis was found on MS medium containing 0.1 mg/l NAA plus 3 mg/l BA. [ABSTRACT FROM AUTHOR]

In vitro regeneration of Melia azedarach L. was studied. Shoots were regenerated from calli initiated from leaflets of in vitro growing plants. The best medium for establishment of cultures was Murashige and Skoog (MS) medium with 4.44 μM benzylaminopurine (BAP) + 0.46 μM kinetin (KIN) + 16.29 μM adenine sulphate (ADE). Regenerated shoots were multiplied in MS + 0.44 μM BAP + 0.37 μM KIN + 3.26 μM ADE. Maximal rooting of 89 % was achieved by culture of regenerated shoots in MS + 12.26 μM indole-3-butyric acid for 3 d and subsequently in MS lacking growth regulators for 27 d. Rooted shoots were acclimatized and successfully transferred to soil. [ABSTRACT FROM AUTHOR]

A study was made on the effect of a number of chemicals (benzimidazole, cycloheximide, gibberellic acid, kinetin, spermidine and spermine) and some of their combinations on the longevity of the leaf disks cut from Populus × euramericana '1-488' and P. alba cv. hickeliana. Benzimidazole and gibberellic acid maintained the leaf disks for varying periods to a miximum ol 80 days, depending on the concentration employed. In a factorial experiment of 3 chemicals × 2 concentrations × 2 cultivars × 2 races of the fungus, it was found that all these factors contributed significantly (P <0.05) to the experimental variance. However, differential effects of the chemicals or the concentrations on the cultivar × race interaction were not observed. The implications of these results in the usefulness of the detached leaf culture of are discussed. [ABSTRACT FROM AUTHOR]

Adventitious shoots were induced on transversally divided expanding leaves from Fagus sylvatica shoot cultures of juvenile origin. Adventitious shoot buds formed mainly on callus that developed on the petiole stump or on the cut across the midrib of distal leaf halves. However, sometimes they arose directly from leaf tissue. An anatomical study confirmed both the direct and indirect origin of the adventitious buds. The best results were obtained by culturing proximal leaf sections on woody plant medium supplemented with 2.9 μ M indole-3 acetic acid in combination with 8.9 μ M benzyladenine or 2.3 μ M thidiazuron (TDZ). Proximal explants were more responsive than distal explants in terms of both callus formation and bud regeneration, regardless of the induction medium or clone tested. Bud formation capacity was influenced by the genotype of the stock shoot culture and was enhanced by an initial 10 d darkness, but was inhibited by longer periods of darkness. Caulogenic competence was significantly affected by the duration of exposure to TDZ; in particular, adventitious shoot length was depressed by increasing the exposure period. Three weeks culture with TDZ was the most efficient treatment for shoot production and elongation. Further shoot development was promoted by subculturing the explants to the same medium used for the maintenance of the stock shoot cultures. Shoots so obtained were multiplied and rooted producing plantlets of adventitious origin. [ABSTRACT FROM AUTHOR]

The effects of changes in the concentration of macronutrients on BA-induced caulogenesis from leaves of mature Juniperus oxycedrus cultured on modified Murashige and Skoog or Schenk and Hildebrandt media are reported. The bud-forming capacity of the explants depended mainly on the ratios among the levels of ammonium, nitrate, and potassium. The most favorable media formulations for differentiation of adventitious buds were those with nitrate:potassium, ammonium:potassium, and nitrate:ammonium ratios near 1, around 0.1, and between 9 and 15, respectively. The total ionic strength of the media limited bud induction, but only when a disequilibrium of these ratios was produced. [ABSTRACT FROM AUTHOR]

The morphogenetic capacity of mature Juniperus oxycedrus L. leaves cultured in vitro has been studied, noting nutritive, hormonal, and environmental factors inducing differentiation and development of adventitious shoots. Bud primordia formed directly from the leaves. Highest bud differentiation rates were obtained when the explants were cultured for at least 21 days on a modified Schenk and Hildebrandt solidified medium containing 0.5 μ M benzyladenine under a 16-h photoperiod. Maximum bud development and elongation was achieved on cytokinin-free medium containing 4% (wt/vol) sucrose and 0.05% (wt/vol) activated charcoal. Regenerated shoots were excised and induced to root on media with auxin. Rooting percentages up to 100% were obtained in the presence of 2.5 μ M naphthaleneacetic acid and 4% (wt/vol) sucrose. The inclusion of activated charcoal in the root induction medium drastically reduced the number of rooted shoots. Following conventional procedures, plantlets were ultimately established in soil. [ABSTRACT FROM AUTHOR]

Rapid regeneration of multiple shoots of Paulownia fortunei was obtained from the petiolar ends of leaf explants from in vitro grown shoots. The optimal shoot-inducing treatment was Murashige-Skoog medium supplemented with 4 µM naphthaleneacetic acid and 20 µM N-benzyladenine. Shoot buds were visible in more than 80% of the explants, mainly from the petiolar cut ends, by 7 days in culture. Shoot growth was promoted by transferring explants to fresh medium once every 2 wk. As many as 43 shoots per explant were obtained in 13 wk. Regenerated shoots could be easily rooted and successfully transplanted to a peat-based potting mixture. [ABSTRACT FROM AUTHOR]

Immature gramineous leaves provide a convenient system for comparing the response of cells in culture with their state of differentiation. Callusing frequency is compared with leaf segment position, leaf age and in vivo mitotic activity in Lolium multiflorum. (1) In a succession of one millimeter sections from the immature leaf base, callus was formed from the first and second sections but not the third or subsequent sections. The frequency of those explants callusing decreased with distance from the base of the leaf and with leaf age (or leaf extension growth). (2) In vivo, the proportion of cells in mitosis declined from around 10-14% at the base of young leaves to zero at 5 mm from the base and beyond. Mitotic activity also declined in leaves as they aged, and dividing cells were not observed in leaves 30 days from initiation or older. (3) A high frequency of callus formation was associated with a high mitotic index in the explant. But for corresponding mitotic indices, cells further away from the leaf base were less responsive in culture. (4) It is proposed that cells are becoming differentiated even in highly meristematically active regions of the leaf and concomitantly losing their ability to respond in culture. [ABSTRACT FROM AUTHOR]