Gibberellins in Immature Seeds of Pharbitis nil

A new gibberellin, gibberellin A₂₀ (GA₂₀), was isolated from immature seeds of morning-glory (Pharbitis nil). Its structure was established as 4aα, 7α-dihydroxy-1β-methyl-8-methylenegibbane-1α, 10β-dicarboxylic acid-1→4a lactone (I) on the basis of its physicochemical analysis as well as chemical evidences. GA₂₀ shows marked growth promoting activities on dwarf maize d₂ and d₅ but weak activities on d₁, rice seedling and dwarf pea.     

Isolation of two new gibberellins from immature seeds of Canavalia

Summary Two new gibberellins, Canavalia gibberellin-I (CG-I) and Canavalia gebberellin-II (CG-II), were isolated from immature seeds of sword bean, Canavalia gladiata DC. The molecular formulas C₁₉H₂₂O₇ and C₁₉H₂₂O₆, were assigned to CG-I and CG-II, respectively, on the basis of high resolution mass, infrared and NMR spectra. The growth-promoting effects of CG-I and CG-II on dwarf maize mutants d ₁ and d ₅, rice seedlings and dwarf peas, Progress No. 5, are reported.     

Isolation of gibberellins A26 and A27 and their glucosides from immature seeds of Pharbitis nil

Summary Two new gibberellins, gibberellins A₂₆ and A₂₇ (GA₂₆ and GA₂₇), and their glucosides have been isolated from immature seeds of Japanese morning-glory (Pharbitis nil), together with GA₈ and its glucoside. GA₂₆, GA₂₇ and their glucosides showed only slight growth-promoting activities on seedlings of rice, dwarf maize and cucumber.     

Variations in Endogenous Gibberellins in Developing Bean Seeds II. Changes Induced in Acidic and Neutral Fractions by GA(1)

Immature (8-mm), medium mature (11-mm), and mature green (16- and 17-mm) bean seeds (Phaseolus vulgaris L. cv. Kentucky Wonder and Bountiful) were incubated in gibberellin A₁ solutions for 24 hours at 20°. Extracts from the seeds were separated into nonacidic, acidic ethyl acetate, and acidic butanol fractions. These were chromatographed. The eluates of the chromatograms were tested on Progress No. 9 dwarf peas grown under red light. The level of neutral gibberellin-like substances remained unchanged in immature seed, but they increased markedly in mature green seeds. Coincident with increased levels of the neutral substances, there were significant decreases in acidic ethyl acetate-soluble gibberellin-like substances, including applied GA₁, and in 1 acidic butanol-soluble gibberellin-like substance. Seed incubation in GA₁ brought about increased activity of substance B-II in immature and medium mature seeds. The level of butanol-soluble gibberellin-like substance B-I in seeds of any size was not affected by incubation in GA₁. Considering the marked increases in activity induced in the neutral fraction and the decreases in activity of certain eluates from the chromatograms of the acidic fractions, it was concluded that the neutral fraction may serve as a reserve form of gibberellins in the dry seed. The acidic ethyl acetate substances and substance B-II may be required for normal development of the bean seed.     

Structures of Gibberellins A39, A48, A49 and a New Kaurenolide in Cucurbita pepo L.

The structures of three new gibberellins A₃₀, A₄₈ and A₄₉ and a new kaurenolide, isolated from seeds of Cucurbita pepo L., were elucidated. The structures of GA₃₉, GA₄₈ and GA₄₉ were shown to be ent-3α,12β-dihydroxygibberell-16-ene-7,19,20-trioic acid (1), ent-2α,3α,10,12α-tetrahydroxy-20-norgibberell-16-ene-7,19-dioic acid 19,10-lactone (5) and the epimer at C–12 of GA₄₈ (8), respectively. The kaurenolide was shown to have the structure: ent-6β,7α,12β-trihydroxykaur-16-en-19-oic acid 19,6-lactone (14).     

Identification of gibberellins A17, A25, A45, abscisic acid,phaseic acid,and dihydrophaseic acid in seeds of Pyrus communis

Gibberellin A₁₇, abscisic acid, and 4′-dihydrophaseic acid were identified by GC-MS of derivatized extracts from both immature and mature seeds of pear. Immature seeds also contained phaseic acid, gibberellins A₂₅ and A₄₅, and two presumed mono-hydroxylated derivatives of GA₄₅, one of which was tentatively identified as 3β-hydroxy-GA₄₅. Several presumed metabolites of abscisic acid were detected in both mature and immature seeds.     

Isolation and Characterization of Gibberellins in Calonyction aculeatum and Structures of Gibberellins A30, A31, A33 and A34

Four novel gibberellins GA₃₀, GA₃₁, GA₃₃, GA₃₄, five known gibberellins GA₈, GA₁₇ (free acid and its monomethyl ester), GA₁₉, GA₂₇, GA₂₉ and the gibberellin-like substances were isolated from immature seeds of evening-glory (Calonyction aculeatum). The structures of GA₃₀, GA₃₁, GA₃₃ and GA₃₄ were elucidated as IX, XVIII, XXII and XXXIV, respectively. The three gibberellin-like substances were partially characterized.     

Three Novel Gibberellins Produced by Gibberella fujikuroi

Three novel gibberellins, GA₅₄ (ent-1α, 3α, 10-trihydroxy-20-norgibberell-16-ene-7, 19-dioic acid 19, 10-lactone), GA₅₅ (ent-1α, 3α, 10, 13-tetrahydroxy-20-norgibberell-16-ene-7, 19-dioic acid 19, 10-lactone) and GA₅₆ (ent-2β, 3α, 10, 13-tetrahydroxy-20-norgibberell-16-ene-7, 19-dioic acid 19, 10-lactone) were shown to occur in the culture broth of Gibberella fujikuroi. Their structures were determined mainly by mass spectrometrical comparison of the derivatives with those of authentic compounds prepared from known gibberellins.     

Microbiological conversion of 12-oxygenated and other derivatives of ent-kaur-16-en-19-oic acid by Gibberella Fujikuroi, mutant B1-41a

The metabolism of several ring C and D-functionalized ent-kaur-16-en-19-oic acids by cultures of Gibberella fujikuroi, mutant B1-41a, to the corresponding derivatives of the normal fungal gibberellins (GAs) and ent-kaurenoids is described. A range of 12α- and 12β-hydroxyGAs and ent-kaurenoids are characterized by their mass spectra and GC Kovats retention indices. The mass spectral and GC data are used to identify the 12α-hydroxy derivatives of GA₁₂, GA₁₄, GA₃₇ and GA₄ (GA₅₈), and of the 12β-hydroxy derivatives of ent-7α-hydroxy- and ent-6α, 7α-dihydroxykaurenoic acids, in seeds of Cucurbita maxima. Similarly the metabolites of GA₉, formed in seeds of Pisum sativum and cultures of G.fujikuroi, mutant B1-41a, are identified as 12α-hydroxyGA₉. ent-11β-Hydroxy- and ent-11-oxo-kaurenoic acids are metabolized by the fungus to the corresponding 11-oxygenated derivatives of the normal fungal ent-kaurenoids and some C₂₀-GAs; no 11-oxygenated C₁₉-GAs are formed. Grandiflorenic acid, 11β-hydroxygrandiflorenic acid, attractyligen and ent-15β-hydroxykaurenoic acid are metabolized to unidentified products.     

Isolation and Characterization of Gibberellins in Mature Seeds of Phaseolus vulgaris

The change of endogenous gibberellin in the germinated seeds of Phaseolus vuigaris cv. Kentucky Wonder was investigated. Based on this result, endogenous gibberellins in the mature seeds were extensively investigated to result in the isolation of GA₁, GA₈, GA₈ glucoside, AB-II (unknown gibberellin-like substance) and glucosyl esters of GA₁, GA₄, GA₃₇ and GA₃₈.     

Isolation of water-soluble gibberellins from immature seeds of Pharbitis nil

Summary The presence of three water-soluble gibberellins was confirmed in immature seeds of morning-glory (Pharbitis nil). The structure of the main component has been elucidated as 2-O--glucosyl-gibberellin A₃. It shows marked growth-promoting activity on rice seedlings but is far less active on dwarf maize mutants d ₁, d ₂ and d ₅.     

Purification and partial characterization of a gibberellin 2β-hydroxylase fromPhaseolus vulgaris

A gibberellin 2β-hydroxylase has been purified from mature seeds ofPhaseolus vulgaris. The enzyme is of molecular weight 36,000 and has the characteristics of a dioxygenase; the cofactors areα-ketoglu-tarate, Fe²⁺ and ascorbate, and activity is stimulated by catalase. The V_max of the enzyme is 6.86 nmole h^?1 mg^?1, and the Km values for [1,2-³H₂]GA₁ andα-ketoglutarate are 0.085 μM and 21 μM, respectively. The purified enzyme preparation catalyzes hydroxylation of GA₁, GA₄, GA₉, and GA₂₀ but exhibits a marked preference for the 3-hydroxylated gibberellins as substrate.     

Metabolism of gibberellins in early immature bean seeds

The endogenous free gibberellins in two different stages of immature Phaseolus vulgaris seeds were investigated and GA₁₇, GA₂₀, GA₂₉, a     

Diffusible and Extractable Gibberellins in Bean Cotyledons in Relation to Dwarfisni

Dwarfism in bean plants (Phaseolus vulgaris L.) is investigated in relation to the diffusible and extractable gibberel-lins in cotyledonary tissues. These gibberellins were partitioned into four parts prior to thin layer chromatograplty: non-acidic and acidic ethyl acetate fractions, and non-acidic and acidic butanol fractions. Cotyledonary segments from a tall plant (cv. Kentucky Wonder) seem to diffuse, preferentially acropetally, more gibberellins in each fraction than those from a dwarf plant (cv. Masterpiece). The diffusion increases with the length of the segments and decreases with period after sowing. From experiments on extraetable gibberellins, however, it is concluded that these phenomena actually result from differences in the gibbereliin contents of the tall and the dwarf plants, from differences in the gibberellin contents of the distal and proximal parts of cotyledons, and from the gibberellin contents before and after imbibition. Ten kinds of gibberellin-Iike substances are detectable in the diffusates, exudates and extracts from the cotyledons of both the plants; two in the non-acidic ethyl acetate, three in the acidic ethyl acetate (GA₁, GA₆ and another), two in the non-acidic butanol, and three in the acidic butanol frac—tion. They are almost identical in quality in the dwarf and tall plants, but in the latter they are more abundant in the cotyledons, particularly in their distal part. With respect to the change in content during the period after sowing, the gibberellin-Iike substances are classified in three groups; unchanging, decreasing (GA₁, GA₆, others) and increasing (butanol soluble glucosyl esters and glucosides of gibberellins)-. The increase of glucose-bound gibberellins and the decrease of free gibberellins during the sowing period suggest the occurrence of conversion. This is obvious only in the tall plants. The gibberellin content in cotyledons is higher in the tall plant than in the dwarf plant. Thus, the marked hypocotyl growth in the tall plants may be dependent on the higher content of gibberellins in their cotyledons and on the higner rate of conversion from free to bound forms.     

Endogenous gibberellins in clover broomrape,a parasitic plant,and its host,clover: Dependency of the parasite on the host for gibberellin production

Endogenous gibberellins were analyzed from a parasitic plant, clover broomrape (Orobanche minor Smith), and its host, clover (Trifolium repens L.). Members of both the early-13- and the early-non-hydroxylation pathways were identified from both the parasite and the host (GA₁₂, GA₂₄, GA₉ GA₄, GA₄₄, GA₁₉, GA₂₀, and GA₁ from clover broomrape; GA₉, GA₄, GA₄₄, GA₁₉, GA₂₀, and GA₁ from clover). Quantitative analyses showed that GA₄₄ was present at high levels in both host and parasite. The similarity in the gibberellins suggests the possibility that the major gibberellins in clover broomrape are transported from clover. However gibberellins such as GA₅₈, GA₃₈, and notably GA₄₇ which was identified from a plant for the first time were detected only from clover broomrape, suggesting that the parasite may have the ability to produce at least those gibberellins     

Isolation and Characterization of Plant Growth Substances in Immature Seeds and Etiolated Seedlings of Phaseolus vulgaris

From the immature seeds of Phaseolus vulgaris cv. Kentucky Wonder GA₁, GA₈, GA₃₈, ABA and GA₈ glucoside were isolated, and GA₄, GA₅, GA₆ and GA₃₇ were identified by GC or GC-MS. Unknown substance, AB–II, was also suggested to be present in the immature seeds. In the etiolated seedlings glucosyl esters of GA₁ and GA₃₈ were identified by GC. GA₈ glucoside and AB–II were shown to be present by the histograms.     

Gibberellin Structure-Dependent Interaction between Gibberellins and Deoxygibberellin C in the Growth of Dwarf Maize Seedlings

The effects of 3-deoxygibberellin C (DGC) on the growth-promoting actions of gibberellins A₁, A₂, A₃, A₄, A₅, A₇, A₈, A₉, A₁₃, A₁₈, A₁₉, A₂₀, and A₂₃ (GAn) as well as 13-deoxygibberellin A₅ (deoxy-GA₅) were tested with seedlings of gibberellin-deficient dwarf mutants (d₂ and d₅) of maize (Zea mays L.). It was found that DGC promoted the actions of gibberellins having both C-1 double bond and C-3 axial hydroxyl group, and it inhibited the action of gibberellins having the saturated ring A and lacking the C-3 axial hydroxyl group, whereas it did not affect that of the ones having the hydroxyl group. The presence of C-2 double bond, as in GA₅ and deoxy-GA₅, diminished the inhibitory action of DGC. The DGC inhibition was alleviated by raising the doses of the relevant GAs, suggesting that it is a competitive inhibition. These results and the finding that the growth of normal maize and rice seedlings are inhibited by DGC indicate that GA₉, GA₁₉, GA₂₀ or other gibberellins having ring A of the same structure are involved in the growth of these plants as active form(s) or as intermediate(s) leading to the active form(s).     

Stimulatory effect of ethephon,ACC, gibberellin A3 and A4+7 on germination of methyl jasmonate inhibited Amaranthus caudatus L. seeds

Methyl jasmonate (JA-Me) inhibited or retarded germination of Amaranthus caudatus seeds in darkness at 24°C, Ethephon, ACC and gibberellins (GA₃ or GA₄₊₇) partially or completely reversed this inhibition depending on the concentration of JA-Me applied. Both ethephon and the gibberellins were more effective than ACC. Both GA₃ and GA₄₊₇ enhanced the stimulatory effect of ethephon or ACC on germination of seeds inhibited by JA-Me.Abbreviations ACC 1-aminocyclopropane-1-carboxylic acid - JA jasmonic acid - JA-Me methyl jasmonate     

Biologically active gibberellins in immature seeds of Pyrus serotin

Biologically active gibberellins were isolated from immature seeds of Japanese pear (Pyrus serotina). The major one was tentatively identified as GA₄ by selected ion monitoring. Evidence for the possible presence of GA₇ in the seeds was inconclusive but GA₃ was not detected by either the rice seedling or barley half-seed bioassay.     

Metabolism of ent-kaurenol-[17-14C], ent-kaurenal-[17-14C] and ent-kaurenoic acid-[17-14C] by germinating Hordeum distichon grains

Subcellular fractions from germinated barley embryos, chloroplast preparations and whole germinating barley grains are able to carry out the conversions ent-kaurenol → ent-kaurenal → ent-kaurenoic acid → ent-hydroxykaurenoic acid, the initial steps of the biosynthetic pathway to gibberellins. Whole grains, and chloroplasts to a slight extent, incorporate radioactivity from ent-kaurenol-[17-¹⁴C] and ent-kaurenoic acid-[17-¹⁴C] into materials with similar but distinct properties from the gibberellins GA₁, GA₃, GA₄ and GA₇.