Relationship between vegetative and rhizome characters and final rhizome yield in micropropagated ginger plants (Zingiber officinale Rosc.) over two generations

Correlation and path analysis for yield and yield contributing characters in two types of micropropagated ginger plants (plantlets directly regenerated from aerial stem explants and plantlets regenerated from aerial stem derived callus) were carried out over first and second generations in two varieties viz. var. ‘Jamaica’ and var. ‘Varada’. Irrespective of the regeneration method, the in vitro derived plants showed high positive correlation and maximum positive direct effect of circumference of cormlets, length of cormlets and number of cormlets with the rhizome yield in the first generation. But tiller number exhibited negative correlation and negative direct effect with the rhizome yield in the first generation. In the second generation of the aerial stem regenerated plants, tiller number, number of nodes per cormlets, circumference of cormlets, number of cormlets and plant height exhibited high positive correlation and maximum direct effect with rhizome yield. However, in the second generation also, the callus regenerated plants showed the same trend as in the first generation. Even though the tiller number showed positive significant correlation with rhizome yield, it showed negative direct effect with the yield.     

Culture method and photosynthetic photon flux affect photosynthesis,growth and survival of Limonium ‘Misty Blue’ in vitro

Microcuttings (shoots each with two leaves) of Limonium ‘Misty Blue’ were cultivated in vitro for 28 days under photoautotrophic (sucrose-free culture medium; CO₂ and photosynthetic photon flux (PPF) enriched conditions), photomixotrophic (medium with 30 g l⁻¹ sucrose; CO₂ and PPF enriched conditions) and heterotrophic (medium with 30 g l⁻¹ sucrose; CO₂ non-enriched conditions) methods. Several growth variables were measured during and at the end of cultivation: shoot fresh and dry weight, percentage of shoot dry matter, root fresh weight, number of leaves, leaf area, chlorophyll and sugar content of leaves, stomatal density and size, net photosynthetic rate (NPR) and percent survival of plantlets ex vitro. Plantlets grown in photoautotrophic and photomixotrophic methods had more leaves, high chlorophyll and sugar contents, high NPR, and showed high percent survival. However, these plantlets possessed less number of stomata per square millimeter. In contrast, the plantlets grown by the heterotrophic method showed decreased values of these growth variables except for the number of stomata per square millimeter. These results indicate that CO₂ enrichment for plantlets in vitro at a relatively high PPF would promote photosynthesis and hence growth of chlorophyllous explants/plantlets in vitro. The resulting plantlets were acclimatized better and sooner on ex vitro transplantation.     

The physiology of Cymbidium plantlets cultured in vitro under conditions of high carbon dioxide and low photosynthetic photon flux density

Summary

Cymbidium plantlets were grown in vitro under conditions of high CO₂ and low photosynthetic photon flux density using the Miracle Packt culture system. Shoots and roots of plantlets showed differential growth characteristics. Shoot growth was not different in plantlets cultured under CO₂-enriched (CDE) and non-enriched (NCDE) conditions. Root growth was promoted in plantlets cultured under CDE in the presence or absence of 2% sucrose (S) with rockwool (R) as the supporting material. Growth was poor in plantlets cultured in 1% agar. Root growth was best in plantlets cultured under CDE R+S. Sucrose is still an important component for root growth under CDE conditions even though CO₂ can be used as an alternative carbon source. Photosynthetic measurements (CO₂ uptake and total Rubisco activity) showed the presence of active and operational photosynthetic machinery in plantlets cultured under CDE and NCDE conditions. The apparent lack of photoautotrophy (as evident from the lack of starch grains in chloroplasts) in plantlets cultured under NCDE conditions is not the result of a lesser potential for photoautotrophy; rather it is a consequence of sub-optimal CO₂ concentrations within the culture vessels.     

Protocol for rapid propagation,and to overcome delayed rhizome formation in field established in vitro derived plantlets of Kaempferia galanga L.

Single medium based efficient protocol for rapid propagation, and to overcome the delayed rhizome formation in field established in vitro derived plantlets of Kaempferia galanga L. through in vitro rhizome induction was achieved. MS medium with combination of 8.87 μM N⁶-benzyladenine (BA), and 2.46 μM indole-3-butyric acid (IBA) induced a mean of 6.2 shoots per explant. Addition of 11.7 μM silver nitrate to 8.87 μM BA and 2.46 μM IBA supplemented medium facilitated the highest number of shoots (mean of 8.3 shoots) as well as roots within 60 days. Subculture of isolated shoots on medium with the same concentration of BA, IBA and silver nitrate increased the number to a mean of 12.1 shoots. Silver nitrate enriched medium developed rhizome at the base of shoots. Increase of sucrose concentration (6–8%) in medium with BA, IBA and silver nitrate favoured the best rhizome development. Ninety five per cent of the plantlets survived in field conditions. The plantlets established in field without in vitro developed rhizome (from medium with BA and IBA) did not form rhizome even at 7 months after transplantation. Instead, they developed tuberous roots only. The plantlets with in vitro developed rhizome (on medium having BA, IBA, silver nitrate, and 6–8% sucrose), and that established from conventional way (through splitting of old rhizome) showed no difference in growth of the rhizome. The present study emphasizes the efficacy of silver nitrate and sucrose to develop rhizome in vitro, which enabled to overcome the delayed development of rhizome, and reduced yield of plantlets established in field without in vitro developed rhizome.     

Variation in two Begonia × hiemalis clones after in vitro propagation

In order to study the variation of Begonia × hiemalis after in vitro propagation, one plant of ‘Aphrodite Pink’ and one of ‘Schwabenland Red’ were vegetatively propagated in four ways. One group of plants was obtained by propagation by means of cuttings. For the second group, the bacterial elimination system, as developed by Hakkaart and Versluijs (1983), was applied which includes an in vitro propagation step. The third and fourth groups were obtained by adding one and two cycles, respectively, of in vitro propagation after the bacterial elimination, so that one, two and three propagation cycles could be compared. One cycle, followed by bacterial elimination, gave nearly uniform offspring. However, when this was followed by one or two cycles of in vitro propagation, the variation increased. Variation also increased when the size of the plantlets obtained in vitro decreased. Thus, an important source of variation can be avoided by eliminating the smallest in vitro plantlets. It is recommended to flower and select the plants before propagation by conventional cuttings, whether or not a further in vitro propagation is applied after the bacterial elimination.     

An effective in-vitro acclimatization using uniconazole treatments and ex-vitro adaptation of Phalaenopsis orchid

The in-vitro acclimatization of Phalaenopsis plantlets under photoautotrophic conditions, with 0 (control), 3.43, 6.86 and 13.72 μM uniconazole (UCZ) treatments for 30 days was investigated before the plantlets were transferred to ex-vitro environments for 14 days. The physiological and growth characters of in-vitro acclimatized, and ex-vitro adapted plantlets were measured. Chlorophyll a (Chl_a), chlorophyll b (Chl_b), total chlorophyll (TC) and total carotenoid (C_x+c) content in plantlets treated with 6.86 μM UCZ were maintained at higher levels than those in plantlets of the control, by 1.82, 1.85, 1.83 and 1.93 times, respectively, leading to enrichment of the pigments in ex-vitro conditions. The maximum quantum yield of PSII (F_v/F_m), photon yield of PSII (Φ_PSII), photochemical quenching (qP) and non-photochemical quenching (NPQ) in UCZ treated plantlets and in ex-vitro adaptation were not significantly different. Proline was accumulated in the control plantlets in both in-vitro acclimatization and ex-vitro conditions, while proline in those plantlets with UCZ treatments was maintained at a low level, which was defined by unstressed conditions. Net photosynthetic rate (P_n) in 6.86 μM UNZ treated plantlets peaked at a higher level than that of the control plantlets, both in-vitro and ex-vitro, by 3.27 and 2.93 times, respectively. In addition, proline content and P_n were inversely related in both in-vitro acclimatization and ex-vitro adaptation. The P_n in UCZ acclimatized plantlets was negatively correlated with plant dry-weight. In-vitro photoautotrophic Phalaenopsis plantlets were successfully acclimatized using a 6.86 μM UCZ treatment which caused them to adapt quickly to ex-vitro environments.     

The influence of illumination levels of daylength extension on yield of winter-grown gladioli in Queensland

The yields of inflorescences, corms and cormlets, and inflorescence quality of winter gladioli were studied under varying illumination levels of 12 hour daylength extension ranging from 0 to 333 lux. The illumination level of the daylength extension for each plot depended on its distance from 2 tungsten halogen light sources mounted at 6 m above ground on poles spaced 8 m apart. The lamps were adjusted for wide beam distribution and aimed at points on the ground 8 m from the base of the poles.Inflorescence yield was increased by increasing the illumination level of daylength extension. The relationship between horizontal illumination level in lux (x) and number of inflorescences (y) was described byy=27.3?10.9 exp(?0.02x)Ninety-seven % of maximum inflorescence yield was obtained at a daylength extension illuminance of 144 lux, while 97% of the maximum number of florets per spike and the other flower quality characteristics were obtained at a daylength extension illumination level of approximately 100 lux. Ninety-seven % of the maximum number of days to flowering was approached at a daylength extension illuminance of 45 lux.There was no clear relationship between the illumination level of daylength extension and number and weight of new corms, or the average weight of each new corm. However, the weights of cormlets per plot and per new corm were higher from plants which received no daylength extension.The commercial application of tungsten halogen lamps to provide daylength extension for winter gladioli production is discussed.     

Morpho-physiological disorders in in vitro culture of plants

The special conditions during in vitro culture results in the formation of plantlets of abnormal morphology, anatomy and physiology. Tissue culture conditions that promote rapid growth and multiplication of shoots often results in the formation of structurally and physiologically abnormal plants. They are often characterized by poor photosynthetic efficiency, malfunctioning of stomata and a marked decrease in epicuticular wax. Qualitatively also, the waxes present on the surface of the leaves of in vitro cultured plants may vary. The conditions under which most laboratories done tissue culture is high relative humidity and low light, no supplemental CO₂, high sucrose and nutrient containing medium may contribute to a phenotype that cannot survive the environmental conditions when directly placed in a greenhouse or field. Understanding these abnormalities is a prerequisite to develop efficient transplantation protocols. The present review summaries the major abnormalities in in vitro culture of plants and also highlight the current and developing methods that are satisfactory for acclimatization of in vitro cultured plantlets.     

High frequency plantlet regeneration from callus and artificial seed production of rock plant Pogonatherum paniceum (Lam.) Hack. (Poaceae)

Pogonatherum paniceum (Lam.) Hack. is a rock plant with good potential for vegetative recovery on naked lands. A high frequency in vitro regeneration system was developed for P. paniceum. Calli were induced from explants of mature seeds, seedlings, young leaves, and stem segments on Murashige and Skoog (MS) medium supplemented with 1.0 mg L⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D), 2.0 mg L⁻¹ α-naphthalene acetic acid (NAA) and 0.2 mg L⁻¹ 6-benzylaminopurine (BAP). High induction rates (59.57%) and regeneration rates (100%) were obtained from mature seed explants; calli were sub-cultured for over 2 years and still retained a high regenerative capacity. One seed explant resulted in 69,997 plants in 1 year. Shoot buds derived from calli were used for encapsulation in liquid MS medium containing 3% sucrose and two different alginate matrices (3% sodium alginate (w/v) + MS medium containing 3% sucrose and 3% sodium alginate + 1% activated carbon (w/v) + MS medium containing 3% sucrose) with a 20-min exposure to 2% CaCl₂ and 0.3% bavistin (w/v). The capsule with 3.0% sodium alginate (w/v) and 1% activated carbon (w/v) showed a higher conversion rate (61.58%) and stronger plantlets under non-aseptic conditions. These systems are useful for the rapid clonal propagation and dissemination of artificial seed material of P. paniceum for eco-recovery.     

Continuous propagation of tomato plants by means of callus cultures

Callus obtained in vitro from stem internode tissue was used to investigate the possibilities for accelerated vegetative propagation of Lycopersicum esculentum Mill. and Lycopersicum peruvianum (L). The results of different tests with phytohormones pointed to a high endogenous auxin level in the original stem explants of L. peruvianum. In L. esculentum shoots were obtained when high amounts of zeatin or coconut-milk were applied.Explants of CCC-pretreated (2 chloroethyl trimethyl-ammonium chloride) tomato plantlets showed a significant increase in shoot formation as compared to the untreated ones.Callus tissue that was more than 2 years old and had been used in 30 transfers still had the capacity to produce normal shoots and roots.More than 200 resulting plants were observed in glasshouse conditions for possible genetic variations. No striking deviations from the original phenotype occurred. Seeds harvested from the fruits of self-fertilized flowers on these plants were sown under normal growth conditions. Some plants of one particular cultivar showed signs of accentuated vegetative development.     

Factors affecting differentiation and growth in vitro,and a mass-propagation scheme for Begonia × hiemalis

Effects of physical and chemical factors on differentiation and growth of Begonia × hiemalis Fotsch, cultivar ‘Schwabenland Red’, in vitro were examined, and a mass-propagation scheme was established. In shaking-culture, differentiated buds grew rapidly into large aggregates of plantlets without roots. They were divided into plantlets and then transferred to an agar medium for rooting. Theoretically, by this method 10¹⁴ or more plantlets may be produced in one year from a 7 × 7-mm young leaf segment.     

Encapsulation of shoot tips of guava (Psidium guajava L.) for short-term storage and germplasm exchange

Shoot tips obtained from in vitro grown plantlets of guava (Psidium guajava L.) were encapsulated in calcium alginate beads for short-term storage and germplasm exchange. A gelling matrix of 3% sodium alginate and 100 mM calcium chloride was found most suitable for formation of ideal calcium alginate beads. Maximum percent response for conversion of encapsulated shoot tips into plantlets was obtained on growth regulator free full strength liquid MS medium. The regrowth ability of encapsulated shoot tips was affected by medium strength and sucrose concentrations in the medium. Encapsulated shoot tips could be stored at low temperature (4 °C) up to 30 days with a survival frequency of 25%. After 60 days of storage under minimal growth conditions (sucrose lacking medium), about 75% encapsulated shoot tips were converted into plantlets when subcultured on 3% sucrose containing medium. Plantlets regenerated from encapsulated shoot tips were acclimatized successfully.     

那贺川野菊的离体保存

以那贺川野菊为试材,研究了不同浓度蔗糖和多效唑（PP333）对试管苗离体保存的影响,并对保存材料再生后代的遗传稳定性进行了分析。结果表明：常温（23 ± 2）℃、光照强度2 000 ~ 3 000 lx、光照时间12 h • d-1的培养条件下,在MS + 2.0 mg • L-1 KT + 0.1 mg • L-1 NAA + 6.5 g • L-1琼脂培养基中,蔗糖浓度为15 ~ 30 g • L-1时附加6 ~ 9 mg • L-1 PP333能保存试管苗360 d以上,存活率达93.53% ~ 100%,且恢复生长后试管苗长势良好,其再生后代的形态特征、过氧化物酶（POD）酶谱和ISSR-PCR扩增图谱与对照相比没有明显差异。     

Response of gladiolus (Gladiolus spp) plants after exposure corms to chitosan and hot water treatments

The state of Morelos, Mexico has gradually become an important producer of gladiolus. Some preconditioning treatments of corms are empirically done causing uneven emergence and low quality of flowers. In this investigation, before planting, gladiolus corms var. ‘Blanca Borrego’ were dipped in chitosan (chitosan reagent and commercial chitosan Biorend^®), in hot water at various temperatures and in treatments combined with Biorend^® at 1.5% and hot water. Results indicated that the most influenced variables were corm germination, number of flowers per spike, number of cormlets and vase life. Overall, the commercial product Biorend^® at 1.5% accelerated corm emergence in approximately 4 days, the number of flowers increased by 2–7 and the vase life extended for 3 days. The number of cormlets was also duplicated. Corms dipped in the commercial chitosan Biorend^® at 1.5% at different intervals of time were not greatly affected except for the emergence and number of cormlets. However, for this experiment there were significant effects on the number of leaves and flowers because of the interactions between chitosan and the immersion time. The temperature of 55 °C affected plant development because emergence was delayed by 6 days; and there were less number of leaves, flowers and cormlets. On the other hand, the incidence of Fusarium oxysporum in naturally infected corms was 0% at temperatures of 55 °C and 50 °C. Immersion times (0, 10, 15 and 20 min) in hot water at 50 °C did not show significant effects on plant development and vase life. Corms dipped in Biorend^® at 1.5% and hot water at 50 °C accelerated their emergence for about 1–7 days, the number of flowers increased by two, extended the storage life for 1–3 days and increased the number of cormlets. The integration of these two treatments -Biorend^® and hot water- might be a good option for increasing the gladiolus plant quality and vase life.     

Vegetative propagation of carnation in vitro through multiple shoot development

Vegetative shoot cuttings of 6 cultivars of carnation (Dianthus caryophyllus L.) were irradiated with 30 or 60 Gy X-rays. Subsequently, from both control and irradiated cuttings, explants were excised at 2 positions of the stem and cultured in vitro. The effects of X-ray dose, genotype and explant position on multiple shoot development of in vitro-cultured nodal stem explants, and on root formation of sub-cultured shoots, were examined. The in vitro propagation method resulted in the production of 2220 plantlets from 209 explants, 4 months after incubation.     

Physiological alterations modulated by rootstock and scion combination in cashew under salinity

In this study we evaluated the influence of rootstocks and scions on physiological disturbances that are induced by salinity in cashew (Anacardium occidentale) plantlets. Two cashew genotypes, CCP 09 and BRS 226, were utilized as rootstocks and scions, resulting in four scion/rootstock combinations by reciprocal grafting. The plantlets were irrigated in absence (control) or in presence of 50 or 200 mM NaCl for 15 days under greenhouse conditions. The plantlets with BRS 226 as rootstocks demonstrated higher transpiration and greater accumulations of Na⁺ and Cl⁻, proline and free amino acids in leaves compared to plantlets that having CCP 09 as rootstocks. The K⁺ content in roots and leaves of all four combinations was not influenced by salinity or by different scion/rootstock combinations. The self-grafting of the BRS 226 genotype showed the highest stability for chlorophyll and Rubisco, exhibiting the highest tolerance to salinity. The scion genotype did not affect any of the studied physiological parameters. The studied physiological disturbances induced by salinity in cashew plantlets were more influenced by rootstock than by scion and these changes were also dependent on compatibility between scion and rootstock.     

Globe artichoke plants obtained from shoot apices through rapid in vitro micropropagation

A rapid method of in vitro propagation for globe artichoke (Cynara scolimus L.) is described. Shoot apices and subterminal stem segments were cultured on modified Murashige and Skoog (1962) medium (MS) with NaH₂PO₄ (50 mg/l), m-inositol (100 mg/l), L-tyrosine (100 mg/l), adenine (40 mg/l), indoleacetic acid (IAA, 0.5 mg/l), kinetin (K, 10 mg/l). sucrose (4%) and agar (0.7%) at pH 5.5. On this medium, a high number of proliferating shoots was obtained. The number of these shoots was increased and their overall development improved by sub-culturing on a MS medium with a reduced concentration of K (5 mg/l) and without the additional amount of sodium dihydrogen phosphate. In these conditions, a 4.5 rate of shoot proliferation was reached after 3 weeks.To induce rooting, the proliferated shoots were transferred to a medium containing half MS, thiamine-HCl (1 mg/l), m-inositol (100 mg/l), ascorbic acid (10 mg/l), naphthaleneacetic acid (NAA, 2 mg/l), sucrose (2%), agar (0.7%) at pH 5.5. In these culture conditions about 84% of plantlets rooted.Cytological analyses performed on root tips of 20 randomly chosen plantlets showed that all the analysed plants contained the diploid number of chromosomes. The plantlets were successfully transferred to soil and the method described seems to be suitable for rapid propagation of globe artichoke.     

非洲菊试管苗叶片的组培快繁

 用非洲菊试管苗叶片作外植体获得了有再分化能力的愈伤组织和正常的再生植株。在适宜培养基上叶片切块的出愈率和出芽率最高可达96 %和90 %; 小苗4 周增殖倍数为10. 85 , 生根率99 % , 最快4周就能从叶片切块成苗。试管苗叶片快繁最适培养基为: 起始MS + 62BA 3. 0 mg·L^-1 + NAA 0. 1 mg·L^-1; 增殖MS + 62BA 3. 0 mg·L^-1 + NAA 0. 2 mg·L^-1; 生根1/ 2 MS + IAA 1. 0 mg·L^-1 。用作外植体的试管苗以3～4叶期为佳, 叶片切块以4 mm ×4 mm为宜。     

试管芋诱导的研究

 以芋组培苗为试材, 研究了蔗糖浓度、激素浓度、光照时间、培养温度、不同大小试管苗,不同芋品种类型等因素对试管芋诱导的影响及不同基质对试管芋育苗成活率的影响。结果表明: 诱导试管芋较理想的培养基为MS + 蔗糖8 % + BA 1. 0 mg·L ^{- 1} + NAA 0. 5 mg·L^-1 , 光照12 h/ d , 培养温度30 ℃; 试管苗越大越有利于试管芋的形成; 试管芋可保持其原有的特性; 基质影响试管芋育苗的成活率, 4 种基质中蛭石最好。