Growth of bean and tomato plants as affected by root absorbed growth substances and atmospheric carbon dioxide

Summary Bean and tomato plants were grown in solution culture root media containing pre-determined concentrations of gibberellin A₃ (GA), 1-naphthaleneacetic acid (NAA), N⁶-benzyladenine (BA), (2-chloroethyl)trimethylammonium chloride (CCC), and at atmospheric levels of 300 and 1000 ppm of CO₂. Net assimilation rates (NAR), relative growth rates (RGR), leaf area ratios (LAR), root to top dry weight ratios (R/T) and changes in dry weight, size, and form of each organ were recorded.Gibberellin had no effect on RGR of either plant species but increased the NAR of tomatoes at 1000 ppm CO₂. Total dry weight was only slightly affected by GA but root growth and R/T were markedly depressed. CCC had no effect on NAR, but decreased RCR and LAR. Root growth of beans and R/T in both plants were promoted by CCC. NAR and RGR were strongly inhibited by BA and NAA. Inhibition of stem and leaf growth by CCC and NAA was greater than that for roots; thus, R/T ratios were increased. Root branching was promoted by NAA.High (1000 ppm), compared to the low (300 ppm), atmospheric levels of CO₂ generally promoted root growth and produced an increase in the R/T, both in the absence and presence of chemical treatment. The multiplicity of effects of the rootabsorbed chemical growth substances and CO₂ on growth and photosynthesis is discussed.Journal article No 3883 of the Michigan Agricultural Experiment Station.NATO Fellow, University of Pisa, Italy.     

NUTRITIONAL AND MORPHOGENETIC INVESTIGATIONS ON CALLUS CULTURES OF NEOMAMMILLARIA PROFILERA MILLER (CACTACEAE)

Neomammillaria prolifera (Cactaceae), when grown on Murashige and Skoog's medium supplemented with fresh coconut milk, showed very little growth. Various concentrations and combinations of growth regulators which did not cause callusing had no apparent effect on the normal growth rates of intact plants. Healthy green calli obtained on a 2,4-D and kinetin-containing medium exhibited extremely fast growth and very specific growth requirements. Relatively high amounts of 2,4-D (10–20 mg/liter), kinetin (1–2 mg/liter), and coconut milk (20–60%) were required at all times for continued proliferation of callus on subculturing. Moreover, the callus was very tolerant to extremely high concentrations of other growth regulators (IAA, NAA, IBA, and GA up to 100 mg/liter) in the presence of 2,4-D and coconut milk. These substances could not replace 2,4-D for callusing or continued growth of callus. It was not possible to establish root cultures or to induce callusing of roots. Attempts to induce differentiation in callus were unsuccessful, except for sporadic root initiation in some cultures. A comparison of these results with similar studies on other succulents demonstrates some basic physiological similarities among this group of plants.     

(2 CHLOROETHYL) TRIMETHYLAMMONIUM CHLORIDE AND RELATED COMPOUNDS AS PLANT GROWTH SUBSTANCES. III. EFFECT ON GROWTH AND FLOWERING OF THE TOMATO

Wittwer, S. H., and N. E. Tolbert. (Michigan State Univ., E. Lansing.) (2-Chloroethyl) trimethylammonium chloride and related compounds as plant growth substances. III. Effect on growth and flowering of the tomato. Amer. Jour. Bot. 47(7) : 560–565. Illus. 1960.—Application of 10^–3 to 10^–7 M solutions of (2-chloroethyl) trimethylammonium chloride, (2 bromoethyl)-trimethylammonium bromide, or (2,3-n-propylene) trimethylammonium bromide to the roots of the tomato plant markedly altered growth and promoted earlier flowering. Treated plants developed thicker stems, and dark-green, savoyed leaves. The growth changes were similar to those produced by exposure to high light intensities and low temperatures, and were opposite to, and more persistent than, those induced by gibberellin. A stepwise regulation in the magnitude of growth and dry matter accumulation in tomato plants followed application of chemicals of increasing concentration to cultural solutions. This growth response varied from a stimulation at 10^–7 M to a marked suppression at 10^–4 M without delay of flowering or visible injury. The control of growth and flowering by the use of these chemicals offers several practical possibilities for their utilization in tomato culture.     

Propagation of lettuce (Lactuca sativa) breeding material by tissue culture

A tissue culture method using Murashige and Skoog's (MS) medium was devised to propagate healthy plants from field grown lettuce plants selected for seed production. Explants (2–3 mm long) from axillary buds were successfully grown on MS + 1.0 or 2.0 mg litre^-1 kinetin and 6.4 mg litre^-1 IAA to promote shoot growth. Concentrations of 0.5 and 4.0 mg litre^-1 kinetin gave poor shoot growth. The cultures were successfully rooted after 3–4 wk on MS + 6.4 mg litres^-1 IAA after transfer from MS + 1.0 mg litre^-1 kinetin and on MS + 4.8 mg litre^-1 IAA after transfer from MS + 2.0 mg litre^-1 kinetin. Concentrations of 3.2 and 8.0 mg litre^-1 IAA gave poor root initiation. Root initiation was more successful when cultures were grown at 40 Wm^-2 than in cultures grown at 5 Wm^-2. Rooted cultures were established in compost with a 90–95% success rate and the regenerated plants flowered c. 18 wk after the cultures were initiated.     

THE CULTURE OF APICAL BUDS OF XANTHIUM AND THEIR USE AS A BIOASSAY FOR FLOWERING ACTIVITY OF ECDYSTERONE

Conditions were developed for the sterile culture of shoot tips of Xanthium pensylvanicum Wallr. for use as a bioassay for flower-controlling chemicals. By using a modified Murashige-Skoog medium (minus the auxin but including kinetin) and light intensity much higher than usual for plant tissue cultures, fast growth and development of the shoot tips was achieved. Under short-day conditions (8 hr day: 16 hr night), the cultures from vegetative shoots flowered and fruited; under noninductive conditions (using a 2 hr light-break in the middle of the dark period), the shoot tips continued vegetative development. Both intact plants and cultured tips could be photoinduced in the first days after germination. Ecdysterone, a potent insect moulting hormone, was tested in the bioassay system. It was without either qualitative or quantitative effect on flowering or vegetative development on either cultured shoot tips or intact plants irrespective of whether they were under inductive or noninductive photoperiodic conditions.     

The Effects of Growth Regulators on Flowering of Chenopodium murale Plants in vitro

In vitro culture of Chenopodium murale L. (ecotype 197) green and herbicide SAN 9789 - treated "white" plants was established and the effects of benzylaminopurine (BAP), indole-3-acetic acid (IAA) and gibberellic acid (GA₃) on growth and flowering were tested. Green plants did not flower on glucose free media, while 17 % of plants flowered on 5 % glucose-containing medium. SAN 9789 (10^–5 M) inhibited growth and flowering. BAP and IAA (0.1 – 5 mg dm^–3) also inhibited growth and flowering of green and "white" plants. GA₃ (10 mg dm^–3) stimulated leaf development in green plants, but had no significant effect on "white" plants, and stimulated flowering of green (41 %) and "white" (33 %) plants.     

Influence of arbuscular mycorrhizal fungi and kinetin on the response of mungbean plants to irrigation with seawater

Increasing use of saline water in irrigation can markedly change the physical and chemical properties of soil. An experiment was carried out to investigate the interaction between the mycorrhizal fungus Glomus clarum, isolated from a saline soil, and kinetin on the growth and physiology of mungbean plants irrigated with different dilutions of seawater (0, 10, 20, and 30%). The growth, chlorophyll concentration and sugar content of mycorrhizal plants was greater than that of non-mycorrhizal plants under all conditions (with or without seawater). The dry weight of both mycorrhizal and non-mycorrhizal mungbean plants irrigated with 10% seawater was significantly increased by treatment with kinetin. The mycorrhizal symbiosis increased root:shoot dry weight ratio, concentrations of N, P, K, Ca and Mg, plant height, protein content, nitrogen or phosphorus-use efficiencies, and root nitrogenase, acid or alkaline phosphatase activities of seawater-irrigated mungbean plants, with little or no effect of kinetin. Kinetin treatment generally decreased chlorophyll concentration and sugar content in mycorrhizal plants as well as Na/N, Na/P Na/K, Na/Ca and Na/Mg ratios. Root colonization by G. clarum was increased by irrigation with seawater, and kinetin had no consistent effect on fungal development in roots. This study provides evidence that arbuscular mycorrhiza can be much more effective than kinetin applications in protecting mungbean plants against the detrimental effects of salt water.     

In vitro propagation of Dendrobium aphyllum (Orchidaceae)—seed germination to flowering

This communication describes asymbiotic seed germination, protocorm development, micropropagation and flowering in in vitro and hardened seedlings of Dendrobium aphyllum (Roxb.) C.E.C. Fischer. Effects of four culture media viz., Murashige and Skoog (MS); Phytamax (Sigma Chemical Co. USA; PM); Mitra et al. (M) and Knudson ‘C’ (KC), 6-benzylaminopurine (BAP) and 2,4-dichlorophenoxyacetic acid (2,4-D), peptone and activated charcoal were studied on seed germination and protocorm development. Maximum germination (97 %) was recorded in PM basal medium. Peptone (2.0 gl^?1) remarkably enhanced germination percentage (100 %), vigorous growth, high survival and subsequent development of protocorms, while in activated charcoal the response was not encouraging. BAP improved germination percentage, however, 2,4-D showed noticeably low seed germination. The morphogenetic response of protocorms and nodal segments of in vitro raised seedlings varied depending on type of explants and concentrations and combinations of plant growth regulators used. Stout root system was induced in 1/2PM + 0.5 mgl^?1 IAA. Approximately 10 % of the in vitro raised plants (4–5 cm) with 3–4 leaves flowered in vitro irrespective of flowering season. The well-rooted plants showed 80 % survival under green house conditions and flowering was noticed after 5–6 months in 10 % of hardened plants.     

Effect of partial defoliation during the vegetative phase on subsequent growth and grain yield of maize

Maize was grown in two densities, 2–47 or 4–94 plants m^-2, and the following treatments imposed: untreated, plants partly defoliated 51 days after sowing, and alternate plants in a row partly defoliated 44 days after sowing. Plants flowered about 82 days after sowing. Leaf area was decreased by 60–64% by defoliation on day 51. Defoliation resulted in decreases in grain yield and grain number of 6–17%, though when alternate plants were defoliated in the higher density there was a substantial decrease in yield and number of grains in defoliated plants, which was largely offset by an increase in adjacent intact plants. When plants were defoliated on day 51 subsequent growth in leaf area was similar to, and that in leaf weight nearly as large as that in untreated plants, while increase in stem weight was substantially less than in untreated plants. By the time of flowering untreated and defoliated plots differed by c. 30% in leaf area. Increments of dry matter after flowering differed by c. 15% between untreated and defoliated plots. The fraction of these increments which entered the grain was c. 90% in both untreated and defoliated plots. When alternate plants in the row were partly defoliated on day 44 their subsequent increase in leaf area was probably 5–16% less than that of the adjacent intact plants. Increments of dry matter after flowering of plots with alternate plants defoliated were 93–95 % of those of untreated plots; leaf efficiency after flowering was slightly greater than in untreated plots. The fraction of the dry matter increment after flowering which entered the grain was c. 88 % in both intact and defoliated plants of the small density, but was 94% in intact plants and 86% in defoliated plants of the large density.     

Eugenol from normal and transformed root cultures of Coluria geoides

Transformed root cultures of Coluria geoides Ledeb. were established with the use of Agrobacterium rhizogenes LBA 9402. Both normal and transformed root cultures were investigated for their growth and yield of eugenol. Normal roots were grown in B5 medium-supplemented with 0.2 mg l^-1 of kinetin and 0.2 mg l^-1 of 1-naphthaleneacetic acid (NAA). Hairy roots grew well in hormone-free B5 medium. Both hairy roots and normal roots produced glycosidic bound eugenol. as with the roots of intact plants, eugenol was the main component of the total essential oils obtained from hairy root and normal root cultures. The yield of eugenol from normal roots was 0.1–0.25% of the dry wt. and depended on the development stage of the culture. Yield of eugenol from hairy roots was 0.08–0.1% of the dry wt. NAA modified the hairy root morphology and influenced the yield of eugenol.Abbreviations NAA 1-naphthaleneacetic acid     

Effects of exogenous cytokinins on flowering of the short-day plantChenopodium rubrum L.

Kinetin at a concentration from 3.10^-6 M to 1.10^-3 M was applied to the plumule ofChenopodium rubrum plants during photoperiodic induction. Different levels of induction were compared (one and three short days). The higher concentrations of kinetin applied to induced plants inhibited flower formation. The rate of leaf initiation was increased under these treatments. Lower concentrations of kinetin (from 3.10^-6 M to 1.10^-5 M) usually promoted lateral bud formation and flowering. The step-wise application of kinetin revealed that the inhibitory effect on flowering had been restricted to the inductive period. The effects of kinetin, benzyladenine and trans-zeatin were compared in plants partially induced by two short days. High concentrations always inhibited flowering. Benzyladenine was the most effective in this respect. Root removal diminished the inhibitory effects of cytokinins on flowering as was stated with benzyladenine. It is assumed that endogenous cytokinins play a role in the regulation of organogenetic activity of the stem apical meristem. Depending on the photoperiodic conditions, they presumably exert their activity by maintaining the vegetative functions of the apex.     

Distribution of 14C-labelled sucrose in seedlings of Pisum sativum L. Treated with indoleacetic acid and kinetin

Summary The influence of decapitation and treatment with IAA and/or kinetin on the pattern of distribution of ¹⁴C-labelled sucrose applied to the third leaf of 14-day old dwarf pea seedlings was investigated. Decapitation resulted in a diversion of the labelled metabolites to the lateral buds, and greatly increased the radioactivity present in the root system indicating that in these seedlings the roots and apex actively competed for translocates from the third leaf. Application of IAA to the decapitated internode prevented the growth of the lateral buds for the duration of the experiment and restored the pattern of distribution of labelled metabolites found in the intact plant. Application of kinetin alone resulted in a marked accumulation of labelled materials in the lateral buds, but when kinetin was applied with IAA metabolites were once again diverted from the lateral buds to the treated internode. Neither of these treatments had any influence on the proportion of the translocated materials which accumulated in the root system when compared with intact plants. The results are discussed in relation to current concepts of hormone-directed transport of nutrients in plants.     

Regulation of flowering by green light depends on its photon flux density and involves cryptochromes

Photoperiodic lighting can promote flowering of long‐day plants (LDPs) and inhibit flowering of short‐day plants (SDPs). Red (R) and far‐red (FR) light regulate flowering through phytochromes, whereas blue light does so primarily through cryptochromes. In contrast, the role of green light in photoperiodic regulation of flowering has been inconsistent in previous studies. We grew four LDP species (two petunia cultivars, ageratum, snapdragon and Arabidopsis) and two SDP species (three chrysanthemum cultivars and marigold) in a greenhouse under truncated 9‐h short days with or without 7‐h day‐extension lighting from green light (peak = 521 nm) at 0, 2, 13 or 25 μmol m^?2 s^?1 or R + white (W) + FR light at 2 μmol m^?2 s^?1. Increasing the green photon flux density from 0 to 25 μmol m^?2 s^?1 accelerated flowering of all LDPs and delayed flowering of all SDPs. Petunia flowered similarly fast under R + W + FR light and moderate green light but was shorter and developed more branches under green light. To be as effective as R + W + FR light, saturation green photon flux densities were 2 μmol m^?2 s^?1 for LDP ageratum and SDP marigold and 13 μmol m^?2 s^?1 for LDP petunia. Snapdragon was the least sensitive to green light. In Arabidopsis, cryptochrome 2 mediated promotion of flowering under moderate green light, whereas both phytochrome B and cryptochrome 2 mediated that under R + W + FR light. We conclude that 7‐h day‐extension lighting from green light‐emitting diodes can control flowering of photoperiodic ornamentals and that in Arabidopsis, cryptochrome 2 mediates promotion of flowering under green light.     

Interaction of Growth Retardants and Temperature in Growth, Flowering, Regeneration, and Auxin Activity of Begonia × cheimantha Everett

Soil application of CCC reduced stem and leaf growth in Begonia plants. This effect was evident with all concentrations tested at 18°C, whereas at 21 and 24°C no growth–retarding effect was observed with 2 × 10^?2 M CCC, and with 5 × 10^?3 M growth was even stimulated. Flowering was promoted by CCC in long day and neur–critical temperature, particularly under low light intensity in the winter. The formation of adventitious buds in leaves of plants grown at 21 and 24°C was stimulated when the plants received 5 × 10^?2 and 2 × 10^?2 M CCC, while 8 7times; 10^?2 M was inhibitory. In plants grown at 18°C bud formation was inhibited by all CCC concentrations. Root formation in the the leaves was usually stimulated by high CCC concentrations, while root elongation was reduced. The level of ether–extractable. acidic auxin (presumably IAA) in the leaves was lowered by CCC treatment of the plants, hut this required higher CCC concentrations at higt than at low temperature. When applied to detached leaves CCC stimulated bud formation at concentrations ranging from 10^?4 to 10^?2 M in leaves planted at 18 and 21°C. At 24°C budding was inhibited by 10^?2 M CCC, the lower concentrations being stimulatory also at this temperature. Root formation and growth were not much affected by CCC treatment of the leaves, but increased with the temperature. Soil application of Phosfon (4 × 10^?4 M) had no effect on growth and flowering, nov did it affect the subsequent regeneration of buds and roots in the leaves. In detached leaves Phosfon stimulated bud formation with au optimum at 10^?6 M. Root formation was stimulated by Phosfon at all temperatures, the optimal concentration being 10^?5 M, whereas root length was conversely affected. Foliar application of B-995 to intact plants and treatment of detached leaves greatly inhibited the formation of buds and had little effect on root formation. B-99D reduced the growth and delayed flowering in the plants.     

SHOOT TIP CULTURE OF HELIANTHUS ANNUUS—FLOWERING AND DEVELOPMENT OF ADVENTITIOUS AND MULTIPLE SHOOTS

Shoot multiplication of Helianthus annuus was optimal from half shoot apices cultured on MS media with 0.1–1.0 mg/1 benzyl adenine or kinetin. Auxins inhibited multiplication and promoted callusing. Rooting was poor and was not promoted by auxins. Flowering of multiple shoots was observed after as little as 3 wk of culture. A number of plant growth regulators and environmental conditions had no effect on flowering which supports the determinate apex theory for sunflower (Habermann and Sekulow, 1972). Adventitious shoots were induced on leaves of the multiple shoots in some inbreds.     

Response of lupins (Lupinus angustifolius L.) and peas (Pisum sativum L.) to Fe deficiency induced by low concentrations of Fe in solution or by addition of HCO3 -

Lupins appear to be more sensitive than peas to Fe deficiency. However, when grown in nutrient solutions between pH 5–6, little difference existed between them in their ability to acidify the solution or to release Fe^III reducing compounds. This experiment was aimed at determining whether differences between species which occurred when Fe deficiency was induced by withholding Fe from an acid solution, are maintained when Fe deficiency is induced by addition of HCO₃ ^-. Lupins and peas were grown in nutrient solutions at 0, 2 and 6 μM of Fe^III EDDHA and either with or without HCO₃ ^- (6 mM). Bicarbonate induced symptoms of Fe deficiency (chlorosis) in both lupins and peas, and markedly decreased the growth of shoots. Symptoms appeared sooner and were more severe in lupins than in peas. Growing plants without HCO₃ ^-, but at the lowest Fe level, decreased the growth and Fe concentration of shoots of lupins but did not induce chlorosis. Growing peas in this treatment, decreased Fe concentrations, but to a lesser extent than in lupins, and did not decrease growth. H⁺-ion extrusion and release of Fe^III reducing compounds was greater in lupins than in peas. Bicarbonate also decreased the growth of roots of lupins but increased the growth of roots of peas. Results indicate that when Fe deficiency is induced by HCO₃ ^-, then the response of lupins and peas are similar to their response in acid solution culture. Differences between species therefore could not be explained by their relative abilities to acidify or release Fe^III reducing compounds. Greater control of the distribution of Fe within the shoots, the presence of a pool of Fe within the roots, a lower threshold for Fe uptake, or a higher content of seed-Fe, may therefore be the reason for the lower sensitivity of peas than lupins to Fe deficiency.     

Salinity and hormone interactions in affecting growth,transpiration and ionic relations ofPhaseolus vulgaris

Addition of either abscisic acid (ABA) or kinetin at 10⁻⁶ M to salinized media (20–120mM NaCl) induced remarkable effects on growth ofPhaseolus vulgaris plants. Whereas ABA inhibited the plant growth and the rate of transpiration, kinetin induced stimulation of both parameters. Moreover, ABA increased proline and phosphorus concentrations in the salinized plants whilst kinetin decreased them. ABA induced stimulation of the transport of K, Ca and Cl from root to shoot, accumulation of K, Na and Cl in root cells and inhibits the transport of Na and accumulation of Ca. Kinetin appeared to inhibit the transport and accumulation of Na and Cl, transport of K, and stimulates the accumulation of K and Ca as well as the transport of Ca. The highest influence of both ABA and kinetin was mostly observed when these hormones were used in combination with the highest concentration of NaCl (120 mM) in the medium.     

The Effect of Exogenous IAA and Kinetin on Nitrate Reductase,Nitrite Reductase and Glutamate Dehydrogenase Activities in Excised Pea Roots

Nitrate reductase (NO₃R) activity, nitrite reductase (NO₂R) activity and NADH₂ dependent glutamate dehydrogenase (GDH) activity were followed in extracts from excised pea roots incubated under aseptic conditions for 9 and 24 h in nitrate containing nutrient medium to which IAA was added in concentrations promoting lateral root formation (1 × 10^?5; 3 × 10^?5; 5 × 10^?5 M) and kinetin in concentrations which reduce lateral root formation (0.1; 1; 5 mg 1^?1, that is 4.65 × 10^?7;4.65 × 10^?6 and 2.3 × 10^?5 M). NO₃R activity was not influenced by IAA, NO₂R activity was slightly depressed by IAA after 24 h incubation and GDH activity was slightly increased after 24 h incubation in the presence of IAA. Kinetin decreased NO₃R activity significantly both after 9 h and 24 h incubation, slightly increased NO₂R activity after 9 h incubation but slightly decreased it after 24 h incubation, and did not affect GDH activity after 24 h incubation. However, when applied together with IAA, kinetin abolished the promoting effect of IAA on GDH activity. IAA neither reversed nor accentuated the effect of kinetin on NO₂R activity. Nevertheless the depressing effect of kinetin on NO₃R activity was emphasized by the presence of IAA after 9 h incubation. The results obtained indicate that reduced nitrate assimilation due to the depression of nitrate reductase activity caused by kinetin probably contributes to the negative growth effect of kinetin in pea root segments grown in nitrate medium.     

Flowering in Pisum: A Fifth Locus, Veg

In addition to the known loci, If, e, sn and hr, a fifth locus,veg, is shown to control flowering in peas. Regardless of thegenotype for the other flowering genes, plants homozygous forthe gene veg did not initiate flower buds under a wide rangeof photoperiod and temperature regimes, including those normallyhighly promotory in peas. Treatment with various plant growthsubstances and grafting to stocks known to promote floweringalso failed to cause initiation. Gene veg prevented expressionof allelic differences at the If locus but segregation for allelesat the sn and hr loci was clearly visible by examination ofseveral vegetative characteristics. For example, sn hr veg andSn hr veg plants showed an opening of the apical bud, productionof lateral branches, and a reduction in growth rate, leafletsize, internode length and stem thickness at approx the sametime as sn hr Veg and Sn hr Veg plants carrying the Lf allelecommenced fruit production, respectively. The graft-transmissibleinhibitor controlled by gene Sn is therefore not specific forthe transition from vegetative to reproductive growth. Geneveg allows the processes leading to apical and foliar senescenceto be examined independently of any effect of flowering andfruiting. We found that gene Sn influenced the total numberof leaves expanded in veg plants but not the time of shoot senescence,which, in plants without flowers and fruits appeared to resultfrom failure of the root system. Pisum sativum L., garden pea, flowering, senescence, genetics     

Effect of phytohormones on plant regeneration in callus culture of <Emphasis Type="Italic">Iris ensata</Emphasis> Thunb

The effect of phytohormones on plant regeneration in callus culture of Iris ensata Thunb. was studied. 2,4-Dichlorophenoxyacetic acid (2,4-D) proved to be the most suitable auxin for the induction and subculturing of morphogenic callus. Organogenic calluses were induced from isolated embryos at the waxphase in MS medium supplemented with 2,4-D (1.0–2.0 mg/l) and kinetin (0.2–0.5 mg/l). Changes in the medium hormonal composition favor the development of adventitious structures. The setting of adventitious shoot buds took place in the presence of 6-benzylaminopurine, while the development of shoots and root primordia was observed after 2,4-D replacement with indoleacetic acid (2.0 mg/l). The root initiation in regenerating plants required a hormone-free medium. The development of intact seedling and regenerated plants of I. ensata were studied. Analysis of the shoot structure demonstrated that in vitro cultured plants are at the juvenile stage.