The effects of hormones and saccharides on growth and flowering of green and herbicides-treatedChenopodium rubrum L. plants

The medium forin vitro culture of green and SANDOZ herbicides-treatedChenopodium rubrum L. plants contained saccharides and hormones in different concentrations. Five days after sowing, the plants were exposed to non-inductive (15 long days—LD) or inductive (6 short days—SD + 9 LD) photoperiodic conditions. The length of hypocotyl and cotyledon blade were measured and percentage of flowering was scored. Gibberellic acid (GA₃) stimulated hypocotyl growth of green and photobleached plants under SD and inhibited under LD conditions. Indole-3-acetic acid (IAA) slightly stimulated hypocotyl growth of green plants only under LD conditions. Benzylaminopurine (BAP) inhibited hypocotyl growth regardless of photoperiodic regime. The optimal concentration of glucose or saccharose for flowering in green and SANDOZ-treated plants was 5%. In green SAN 9785-treated plants exogenous saccharides compensated lack of photosynthates to bring about full flowering, but SAN 9789-treated plants needed in addition GA₃.     

Flowering of Cultivated Green and SAN 9789-Treated Chenopodium rubrum Plants Exposed to White,Blue, and Red Light

Green plants and plants devoid of photosynthetic pigments were compared with regard to their ability to flower under various growth conditions. Green plants of Chenopodium rubrum L. and plants treated with norflurazon SANDOZ-9789 (SAN) were grown on sucrose-containing media with or without hormones (GA₃, BA, IAA, ABA) under short-day photoperiodic or continuous illumination with white, blue, or red light. Green and SAN-treated albino plants produced flowers only under short-day conditions. The flowering of green plants was independent of the presence of sucrose and hormones in the medium as well as of the light quality. The albino plants produced flowers under white and blue light but did not flower in red light. The addition of GA₃ or BA to the medium induced flowering of albino plants exposed to red light. The functional interaction of photoreceptors in the flowering control is discussed.     

The role of GA,IAA and BAP in the regulation of <Emphasis Type="Italic">in vitro</Emphasis> shoot growth and microtuberization in potato

The effect of auxin, GA and BAP on potato shoot growth and tuberization was investigated under in vitro condition. The shoot length of potato explants increased with the increasing of concentrations (0.5 – 10 mg dm⁻³) of IAA treatment especially with the addition of GA₃ (0.5 mg dm⁻³), but was inhibited by BAP (5 mg dm⁻³). The root number and root fresh weight of potato explants increased with the increasing of IAA levels either in the presence of GA₃ (treatment IAA+GA) or not (IAA alone). However, no root was observed in the treatment IAA+BAP, instead there were brown swollen calli formed around the basal cut surface of the explants. The addition of GA₃ remarkably increased the fresh weight and diameter of calli. Microtubers were formed in the treatments of IAA+BAP and IAA + GA + BAP but not observed in the treatments of IAA alone or IAA + GA. IAA of higher concentrations (2.5 – 10 mg dm⁻³) was helpful to form sessile tubers. With the increasing of IAA levels, the fresh weight and diameter of microtubers increased progressively. At 10 mg/L IAA, the fresh weight and diameter of microtubers in the treatment of IAA + GA + BAP were 409.6 % and 184.4 % of that in the treatment of IAA + BAP respectively, indicating the interaction effect of GA and IAA in potato microtuberization.     

Induction and stimulation of in vitro flowering of Pharbitis nil by cytokinin and gibberellin

The influence of BA, GA₃ and IAA applied successively onflower bud formation in shoot apices of Pharbitis nil hasbeen investigated. The shoot apices were isolated from seedlings cultivatedunder non-inductive continuous light and from seedlings exposed to asubinductive (12 h) dark period. BA and GA₃ introducedsuccessively into culture medium replaced the inductive night, causing theflowering of plantlets in completely non-inductive continuous light (optimalconcentration of BA – 10^–7–10^–6mol dm^–3, GA₃ –10^–7–10^–6 moldm^–3) and stimulated this process under thesubthresholdinduction. These hormones applied in reverse sequence (in the first placeGA₃, then BA) did not affect flowering of explants. IAA nullifiedthestimulating effect of BA and GA₃. The influence of phytohormones onflowering may result from the change of growth correlations within the shootapical meristem.     

Shoot Regeneration from Immature Cotyledons of Cicer Arietinum

Shoot regeneration was achieved from immature cotyledons of five chickpea (Cicer arietinum L.) genotypes: C235, ICC4971, ICC11531, ICC12257 and ICC12873. The cotyledons cultured on Murashige and Skoog (MS) medium supplemented with 3 or 5 mg dm^–3 zeatin with or without 0.04 mg dm^–3 indole acetic acid (IAA) showed formation of cotyledon like structures (CLS) at their proximal ends. Subsequently, shoot regeneration took place in some of the CLS forming explants. CLS were also formed in cotyledons cultured on MS + 0.2 – 1 mg dm^–3 thidiazuron (TDZ); direct shoot regeneration was observed in cotyledons cultured on 1 mg dm^–3 TDZ. The shoot buds elongated on media containing indole butyric acid (IBA), benzylaminopurine (BAP) and gibberellic acid (GA₃). Complete plantlets were obtained by rooting of shoots following pulse treatment with 200 mg dm^–3 IBA for 5 min and culture on growth regulator free half-strength MS medium.     

Multiple Shoot Induction from Cotyledonary Node Explants of Terminalia chebula

A protocol for multiple shoot induction from cotyledonary node explants of Terminalia chebula Retz. has been developed. Germination frequency of embryos (up to 100 %) was obtained on Murashige and Skoog (MS) medium supplemented with 0.5 mg dm^–3 gibberellic acid (GA₃). Maximum number of shoots (6.4 shoots per cotyledonary node) was obtained on half-strength MS + 0.3 mg dm^–3 GA₃+ 1.0 mg dm^–3 indole-3-butyric acid (IBA) + 10.0 mg dm^–3 benzylaminopurine (BAP) after 4 weeks of culture. When the cotyledonary nodes along with the axillary shoot buds were allowed to grow in the same medium upto 19.2 shoots were obtained after 8 – 9 weeks. Best rooting (100 %, 5.5 roots per shoot) was observed when shoots were excised and transferred to half-strength MS medium containing 1.0 mg dm^–3 IBA + 1 % mannitol and 1.5 % sucrose. Survival of rooted plants in vivo was low (35 – 40 %) when they were directly transferred to soil in glasshouse. However, transfer to soil with MS nutrients and 1.0 mg dm^–3 IBA in culture room for a minimum duration of 2 weeks increased the survival percentage of plants to 100 %.     

Rapid micropropagation of Woodfordia fruticosa (L.) Kurz (Lythraceae), a rare medicinal plant

A rapid propagation method comprising initiation of in vitro shoot tip culture from field-grown flowering plants and reculture of the nodal segments of regenerated shoots in Schenk and Hildebrandt (1972) medium was developed for Woodfordia fruticosa (L.) Kurz., a rare medicinal shrub. A medium supplement of 6-benzylaminopurine (0.2 mg.l^–1) induced high frequency (88%) development of axillary shoot buds (3.2) in 4–5 weeks. Subculture of the explants with multiple new shoots in fresh medium for 30 days yielded an even larger number (9.7) of shoots. Highest multiplication (26–35 shoots) was recorded when using culture initiation media with 0.5 mg.l^–1 each of BAP and NAA followed by subculture in 0.2 mg.l^–1 BAP. The shoot multiplication rate was further accelerated by reculturing 0.4–0.6 cm nodal segments of regenerated shoots in media with 1.0 mg.l^–1 BAP. Shoot cuttings (3.5–7.0 cm) were rooted in 0.2 mg.l^–1 IAA. Regenerated plants displayed uniform morphological, growth and flowering characteristics.Abbreviations BAP 6-benzylaminopurine - NAA naphthaleneacetic acid - IAA Indole-3-acetic acid - IBA indole-3-butyric acid - SH Schenk and Hildebrandt (1972) medium     

Effect of Growth Regulators on Photosynthetic Metabolites in Cotton under Water Stress

The contents of several photosynthetic metabolites — 3-phosphoglyceric acid (3-PGA), pyruvate, nicotinamide adenine dinucleotide phosphate (NADP) and adenosine triphosphate (ATP) — were determined in leaves of cotton plants (Gossypium hirsutum L. cv. H-777) subjected to waterlogging at vegetative stage, and/or drought at the reproductive stage. In controls, soil moisture contents was kept at field capacity. One day prior to stress, the plant shoots were sprayed with 5 M aqueous solution of indole-3-acetic acid (IAA), gibberellic acid (GA₃), benzylaminopurine (BAP), abscisic acid, and ethrel. In control plants, various growth regulators reduced contents of 3-PGA and ATP while increased contents of NADP and pyruvate. During waterlogging IAA promoted 3-PGA content, and BAP enhanced pyruvate content. During drought, GA₃ enhanced ATP and 3-PGA contents, while IAA enhanced pyruvate content.     

Plant regeneration from shoot apical meristems of Melia azedarach L. (Meliaceae)

A protocol was developed for plant regeneration of Melia azedarach L. by in vitro culture of apical meristem (0.5 mm in length). The influence of six clones was investigated. The culture procedure comprised two sequential steps: 1) Induction of shoots by in vitro culture of axillary buds from adult trees (10–15 years old) by culture on Murashige and Skoog (1962) medium (MS) supplemented with 0.5 mg·dm⁻³ BAP (6-benzylaminopurine), 0.1 mg·dm⁻³ IBA (indolebutyric acid), and 0.1 mg·dm⁻³ GA₃ (gibberellic acid). The Multiplication of the regenerated shoots was achieved in MS + 0.5 mg·dm⁻³ BAP + 0.1 mg·dm⁻³ GA₃. 2) In vitro culture of the apical meristems from the regenerated shoots in MS medium (0.7 %) supplemented with various combinations of BAP and IBA. Maximum shoot proliferation was obtained on MS medium supplemented with 0.5 mg·dm⁻³ BAP and 0.1 mg·dm⁻³ IBA. Regenerated shoots were rooted on MS + 3.5 mg·dm⁻³ IBA (4 days) followed by subculture on MS lacking growth regulators (30 days). Complete plants were transferred to soil.     

Effect of Ecdysterone on Morphological and Physiological Processes in Plants

In order to elucidate the physiological role of phytoecdysteroids in plants, we investigated the effects of exogenous ecdysterone (ECD) and phytohormones (IAA, GA₃, and 24-epibrassinolide (EBL)) on the growth of wheat coleoptiles and Arabidopsis thaliana seedlings (wild-type ecotype Columbia (Col) and its det2 mutant), on -amylase activity in the barley aleurone layer, and on the pigment content in the kidney bean senescent leaves. The range of effective ECD concentrations depended on the type of a reaction to be regulated. The regulation of growth processes was affected by a wide range of ECD concentrations (10^–13–10^–5 M), whereas some metabolic processes, such as the activation of -amylase and the retardation of leaf yellowing, by a narrow range, that is, 10^–9–10^–7 M and 10^–9–10^–8 M, respectively. We noted the synergetic effect of ECD and IAA on coleoptile elongation, the antagonistic effect of ECD and EBL on coleoptile elongation, as well as the antagonistic action of ECD and GA₃ on coleoptile elongation and -amylase activity. The data obtained demonstrate that ECD is a physiologically active compound. ECD might be supposed to act as a source of sterols or a regulator of IAA and protein synthesis. The effects of this regulator seems to be brought about by its interaction with the EBL and GA₃ receptors.     

In vitro multiplication and field establishment of Adhatoda beddomei C. B. Clarke,a rare medicinal plant

Clonal propagation of Adhatoda beddomei C.B. Clarke (Acanthaceae), a rare medicinal shrub, was achieved through callus-free axillary meristem proliferation from stem node explants of field-grown plants cultured in SH medium. Shoot multiplication was a function of cytokinin activity but sustained growth of the shoots was dependent on the synergistic effect with the auxin, IAA. An optimum number of 5–10 shoots per explant were obtained in 6 weeks using 3.0 mg.l^–1 BAP, 0.5 mg.l^–1 2-ip and 1.0 mg.l^–1 IAA, Upon subculture, vertical halves of the precultured node with the differentiated shoots yielded a larger aggregate number of shoots (23–27) than the uncut precultured node left intact (15–17). Shoot multiplication was rapid and consistent over prolonged periods when the hormonal concentrations were reduced to 1.0 mg.l^–1 BAP and 0.2 mg.l^–1 IAA during subculture, and reculture of the nodal explants derived from shoot cultures. Rooting of 3–5 cm shoots thus obtained was greatly accelerated in stationary liquid medium containing 0.2 mg.l^–1 IBA or IAA. Hardening of the rooted plantlets in the humidity chamber was essential for high frequency (95%) survival. Micropropagated plants established in the field flowered after fifteen months and were free from apparent defects in cytological, growth and flowering characteristics.Abbreviations SH Schenk and Hildebrandt (1972) basal medium - BAP 6-benzylaminopurine - 2-ip 2-isopentenyladenine - IAA indole-3-acetic acid - IBA indole-3-butyric acid - NAA 1-naphthaleneacetic acid     

Carbonic Anhydrase,Photosynthesis, and Seed Yield in Mustard Plants Treated with Phytohormones

The leaves of 30-d-old plants of Brassica juncea Czern & Coss cv. Varuna were sprayed with 10^–6 M aqueous solutions of indole-3-yl-acetic acid (IAA), gibberellic acid (GA₃), kinetin (KIN), and abscisic acid (ABA) or 10^–8 M of 28-homobrassinolide (HBR). All the phytohormones, except ABA, improved the vegetative growth and seed yield at harvest, compared with those sprayed with deionised water (control). HBR was most prominent in its effect, generating 32, 30, 36, 70, 25, and 29 % higher values for dry mass, chlorophyll content, carbonic anhydrase (E.C. 4.2.1.1) activity, and net photosynthetic rate in 60-d-old plants, pods per plant, and seed yield at harvest, over the control, respectively. The order of response to various hormones was HBR > GA₃ > IAA > KIN > control > ABA.     

Somatic embryogenesis and plant regeneration in <Emphasis Type="Italic">Catharanthus roseus</Emphasis>

Embryogenic callus in Catharanthus roseus was initiated from hypocotyl on Murashige and Skoog’s (MS) medium supplemented with 1.0–2.0 mg dm⁻³ of 2,4-dichlorophenoxyacetic acid (2,4-D) or chlorophenoxyacetic acid (CPA). Calli from other sources were non-embryogenic. Numerous somatic embryos were induced from primary callus on MS medium suplemented with naphthalene acetic acid (NAA) within two weeks of culture. Embryo proliferation was much faster on medium supplemented with 6-benzylaminopurine (BAP). After transfer to medium with gibberellic acid (GA₃, 1.0 mg dm^{− 3}) mature green embryos were developed and germinated well into plantlets on MS liquid medium supplemented with 0.5 mg dm⁻³ BAP. Later, embryos with cotyledonary leaves were subjected to different auxins treatments for the development of roots. Before transfer ex vitro, plantlets were cultivated on half strength MS medium containing 3 % sucrose and 0.5 mg dm⁻³ BAP for additional 2 weeks. Additionally, the effect of liquid medium has been evaluated at different morphogenetic stages.     

Seed potato (Solanum tuberosum L.) yield and tuber number increase after foliar applications of cytokinins and gibberellic acid under field and glasshouse conditions

The purpose of these experiments is to determine the effects of foliar applications of benzylaminopurine (BAP) and gibberellic acid (GA) on tuber number production of seed potatoes. In field experiments conducted during 1989/90 cv. Mailén was used and BAP, 50 mg·l^–1 was foliarly applied at (1) tuber initiation, 36 days after emergence (DAE); (2) 54 DAE; and, (3) 64 DAE. Under glasshouse conditions, in 1991/92 cv. Spunta was used and BAP 50 mg·l^–1+GA 50 mg·l^–1 were applied 30 and 37 days after planting/transplanting. In 1992 cv. Huinkul, Kennebec and Spunta were used and BAP 50 mg·l^–1+GA 50 mg·l^–1 and Biozyme (Techic SA), a commercial product with auxin (IAA, 32.2 mg·l^–1), gibberellic acid (GA₃, 32.2 mg·l^–1) and cytokinins (zeatin, 83.2 mg·l^–1) at 5 ml·l^–1 were applied. In cv. Mailén, a higher tuber number in the seed fraction (<80 g) was found when BAP was applied at each of the three crop stages, while applications 54 and 62 DAE also increased tuber number in the 80–400 g fraction. As a result of BAP applications, tuber yield was also significantly increased. In the glasshouse experiments, cv. Spunta showed a significant increase in minituber production in 3 out of 4 cases, either if the mother plant came from in vitro generated plantlets or minitubers, or if GA + BAP or Biozyme was applied. It can be concluded that the use of these PGRs under both field and glasshouse conditions in cvs. Mailén and Spunta can result in increased tuber number in the seed fraction.     

Plant Regeneration Through Somatic Embryogenesis in Leaf Derived Callus of Plumbago Rosea

Regeneration of Plumbago rosea L., a rare medicinal plant, via somatic embryogenesis in callus cultures derived from leaf explants was described. Optimum callus formation was achieved on semi-solid Murashige and Skoog (MS) medium supplemented with 0.25 mg dm^–3 kinetin and 2.0 mg dm^–3 1-naphthaleneacetic acid (NAA). Somatic embryogenesis was achieved upon transferring the 4-week-old callus to a medium containing 1.0 mg dm^–3 kinetic (Kn), 0.5 mg dm^–3 gibberellic acid (GA₃) and 0.1 mg dm^–3 NAA. Embryo maturation and germination was achieved on the half-strength MS basal salts supplemented with 0.01 – 0.25 mg dm^–3 Kn and 2 % (m/v) saccharose. An average of 50 – 60 plantlets were obtained from 150 mg of embryogenic callus within 4 week of subculture. Out of the 50 plantlets about 28 survived in the greenhouse.     

Effect of Darkness on Growth and Flowering of Chenopodium rubrum and C. murale Plants in vitro

Chenopodium rubrum, a short-day plant, and C. murale, a long-day plant, were grown in vitro in continuous darkness. Control C. rubrum plants exposed to continuous darkness for 15 d at cotyledonary phase, did not flower, while 80 % of plants flowered on the medium with 5 % glucose and 10 mg dm⁻³ GA₃. Control C. murale plants exposed to continuous darkness for 10 d at the age of 4^th pair of leaves, did not flower, while GA₃ (1 – 5 mg dm⁻³) stimulated flowering up to 65 %. This revised version was published online in July 2006 with corrections to the Cover Date.     

Micropropagation of sour cherry (Prunus cerasus L.) cv. Šumadinka

Sour cherry cv. umadinka (Prunus cerasus L.) is the leading Yugoslav cultivar for production orchards. A method of micropropagation has been developed for the purpose of growing umadinka on its own roots and for rapid multiplication.Aseptic cultures were initiated from shoot explants 1–2 mm long on Murashige & Skoog medium with (in mgl^-1) 6-benzylaminopurine (BAP): 1, indole-3-yl butyric acid (IBA): 1 and gibberellic acid (GA₃): 0–1.The best medium for proliferation was MS with (in mgl^-1): BAP 0.5, IBA 0.1, GA₃ 0.1, but media with (in mgl^-1): BAP 0.5, NAA 0.1, GA₃ 0.1 and BAP 1, NAA 0.1 and GA₃ 0.1 were also shown to be good. A higher degree of proliferation obtained with some media did not necessarily result in a better quality of plantlets produced.For rooting the best combination of culture medium was achieved with pretreatment 10 days in MS 1/2 with 1 mgl^-1 IBA, followed by transfer to a hormone-free medium after 5–10 days, resulting in 88% success.The rooted plants were planted in containers and acclimatized under mist, with over 90% of plants surviving transplantation.     

Effects of gibberellic acid spray on nitrogen yield efficiency of mustard grown with different nitrogen levels

Mustard is cultivated throughout the world for oil in its seeds. Itrequires high nitrogen input for improved productivity but the nitrogen appliedto the soil is not fully utilised by the crops due to various constraints. Theobjective of the reported research was to determine if foliar- appliedgibberellic acid (GA₃) could enhance crop growth and increasenitrogen-use efficiency. A field experiment was conducted during 1997–98in which GA₃ (10^–5 M) was applied tofoliage at 40d after sowing (pre-flowering) to mustard grown with 0, 40(sub-optimal), 80 (optimal) and 120 (supra-optimal) kgN ha^–1. Foliar spray of GA₃ was effectiveonly when plants received sufficient N (80 kgN ha^–1). GA₃ sprays significantly enhancedplant dry mass, leaf area, carbon dioxide exchange rate, plant growth rate,cropgrowth rate and relative growth rate. GA₃ -treated plants showedenhanced nitrogen-use efficiency through redistribution of N to seeds.     

Plant regeneration in Kentucky bluegrass (Poa pratensis L.) via coleoptile tissue cultures

Summary Plant regeneration in Kentucky bluegrass (Poa pratensis L. cv. Touchdown) via culture of seedling tissues was investigated. When coleoptile, leaf, and stem sections of dark-germinated seedlings were cultured on Murashige and Skoog (MS) medium, different types of callus were produced, depending on the expiant source and growth regulator combinations. Only compact-friable callus (type 3) and moderately compact, friable callus (type 2) produced shoots upon subculture. The nonstructured watery callus (type 4) produced roots without shoots. Shoot differentiation from callus tissues was highest when the culture medium contained 0.2 mgL^–1 picloram + 0.01 mgL^–1 -naphthaleneacetic acid (NAA). Calli grown from coleoptiles had higher shoot regeneration frequency (32%) than that obtained from either stem sections (12%) or young leaf tissues (2%) of the same seedlings. Some organogenic callus lines produced exclusively green plants, while others produced albino shoots or a mixture of green and albino shoots. The green plants were multiplied in a medium containing 0.1 mgL^–1 BAP plus either 0.2 mgL^–1 picloram or 0.1 mgL^–1 indole-3-acetic acid (IAA). Over 90% of the cultures in the shoot proliferation medium produced roots in 4 weeks. The rooted plants were successfully established in soil medium and grown in the greenhouse.Abbreviations BAP 6-benzylaminopurine - 2,4-D 2,4-dichlorophenoxyacetic acid - IAA indole-3-acetic acid - MS Murashige and Skoog (1962) medium - NAA -naphthaleneacetic acid - picloram 4-amino-3,5,6-trichloropicolinic acid - TDZ thidiazuron     

Effects of ascorbic acid on axillary shoot induction in Tylophora indica (Burm. f.) Merrill.

A procedure for rapid in vitro multiplication of Tylophora indica (Burm. f.) Merrill., an important indigenous medicinal plant, has been developed. Addition of ascorbic acid was essential to induce sprouting of axillary buds. Optimum multiplication was observed on MS medium containing 6-benzylamino purine (5.0 mg l^–1), -naphathalene-acetic acid (0.5 mg l^–1) and ascorbic acid (100 mg l^–1). Rooting of in vitro produced shoots was readily achieved with indole-3-acetic acid alone (1.0 mg l^–1) in MS. The plantlets thus obtained were successfully transferred to pots in large numbers which grew normally.Abbreviations BAP 6-benzylamino purine - 2,4-D 2,4-dichlorophenoxyacetic acid - GA₃ gibberellic acid - IAA indole-3-acetic acid - IBA indole-3-butyric acid - 2ip 2-isopentenyladenine - Kn kinetin - MS Murashige & Skoog media - NAA -naphthalene acetic acid