Morphogenesis of the stamenless-2 mutant in tomato. II. Modifications of sex organs in the mutant and normal flowers by plant hormones

1973 ◽  
Vol 51 (12) ◽  
pp. 2473-2479 ◽  
Author(s):  
Vipen K. Sawhney ◽  
Richard I. Greyson
Keyword(s):  
Gibberellic Acid ◽  
Plant Hormones ◽  
Indoleacetic Acid ◽  
Single Gene ◽  
Apparent Effect ◽  
Viable Pollen ◽  
Stamen Development ◽  
Auxin Content

Application of gibberellic acid (GA3) to young plants of a single gene recessive stamenless-2 (sl2/sl2) mutant of tomato produced 'phenocopies' of the normal plants. Unlike the untreated sl2/sl2 mutant, flowers of GA3-treated plants bore no external ovules, possessed more yellow-pubescent stamens and fewer carpelloid stamens per flower, and produced laterally fused stamens. Stamen length at maturity was similar to normal flowers. In addition, viable pollen resembling the normal was produced in GA3-treated sl2/sl2 flowers. It was also found that GA3 was more effective than GA4+7 in inducing stamen development. Normal plants treated with GA3 produced multicarpellary and multilocular ovaries. Indoleacetic acid (IAA) induced the carpellization of stamens in sl2/sl2 flowers but had no apparent effect on the flowers of normal plants. It is proposed that added gibberellins promote maleness in systems where there is an inhibition or abnormality of stamen development, whereas they stimulate femaleness (possibly through an increase in auxin content) in systems with normal stamen development.

Interpretations of determination and canalisation of stamen development in a tomato mutant

1979 ◽  
Vol 57 (22) ◽  
pp. 2471-2477 ◽  
Author(s):  
V. K. Sawhney ◽  
R. I. Greyson
Keyword(s):  
Gibberellic Acid ◽  
Single Gene ◽  
Progressive Increase ◽  
Stamen Development ◽  
Early Stages ◽  
Floral Buds ◽  
Stamen Primordia ◽  
Recessive Mutant ◽  
Tomato Mutant

Floral buds of different sizes of the single-gene recessive mutant stamenless-2 (sl2/sl2) of tomato were treated with gibberellic acid (GA3) and the development of staminal features in each bud was followed. The results show that the application of GA3 to buds with stamen primordia at the early stages of initiation (up to 0.1 mm in length) induced the formation of normal-looking stamens. However, with a progressive increase in stamen size, less and less of the normal stamen features were produced following the GA3 treatment. Ultimately, buds with stamen primordia 0.8 mm long or longer failed to respond to GA3 and produced all the mutant characteristics. These results are discussed in terms of Waddington's concept of “determination” and “canalisation” of development.

Regulation of the fusion of floral organs by temperature and gibberellic acid in the normal and solanifolia mutant of tomato (Lycopersicon esculentum)

1990 ◽  
Vol 68 (4) ◽  
pp. 713-718 ◽  
Author(s):  
K. N. Chandra Sekhar ◽  
V. K. Sawhney
Keyword(s):  
Lycopersicon Esculentum ◽  
Gibberellic Acid ◽  
Ammonium Chloride ◽  
Low Temperatures ◽  
Single Gene ◽  
Gibberellin Biosynthesis ◽  
Growth Substances ◽  
Apparent Effect ◽  
Floral Organs ◽  
Floral Apex

The flowers of a single gene homozygous recessive solanifolia (sf/sf) mutant of tomato (Lycopersicon esculentum) possess separate sepals, petals and stamens, and a gynoecium that consists of several carpels with separate styles. In contrast, in the normal tomato (cv. Pearson), floral organs of each whorl are either partially or completely fused. Different temperature conditions and gibberellic acid treatments had no effect on the ontogenetic fusion of sepals and petals of the mutant and normal flowers. However, low temperatures and gibberellic acid induced the separation of stamens and pistil in many of the normal flowers, and they enhanced the separation of carpels in mutant flowers. In contrast, high temperatures and 2-chlo-roethyltrimethyl ammonium chloride, an inhibitor of gibberellin biosynthesis, promoted the fusion of stamens and gynoecia of mutant flowers, but had no apparent effect on the normal flowers. The nonfusion of stamens and carpels, in both genotypes, was associated with an increase in the number of these organs, whereas their fusion was accompanied with a reduction in their number. It is proposed that the nonfusion of floral organs in the sf/sf mutant is partly related to changes in endogenous growth substances which, through an effect on the size of the floral apex, affect the number and fusion of stamens and carpels.

Growth and Aflatoxin Production by Aspergillus parasiticus in a Medium Containing Plant Hormones, Herbicides or Insecticides

1987 ◽  
Vol 50 (12) ◽  
pp. 1044-1047 ◽  
Author(s):  
R. S. FARAG ◽  
M. A. EL-LEITHY ◽  
A. E. BASYONY ◽  
Z. Y. DAW
Keyword(s):  
Acetic Acid ◽  
Gibberellic Acid ◽  
Plant Hormones ◽  
Aspergillus Parasiticus ◽  
Synthetic Medium ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Inhibitory Effect ◽  
Indol Acetic Acid ◽  
Acid Herbicides

The effect of some widely used plant hormones (indol-3-acetic acid and gibberellic acid), herbicides (gramoxone, stomp and treflan) and insecticides (malathion, actellic and guthion) on Aspergillus parasiticus growth and aflatoxin production in a synthetic medium was studied. Addition of indol acetic acid to the medium increased aflatoxin production more than gibberellic acid. Treflan at 5, 10 and 20 ppm levels caused a highly significant stimulatory effect on A. parasiticus growth and aflatoxin production. In contrast, stomp at 10 and 20 ppm produced the reverse effect. Guthion, an insecticide, caused a marked decrease in fungal growth and aflatoxin production. The inhibitory effect of insecticides under study on both fungal growth and aflatoxin production in effectiveness followed the sequence: guthion>actellic>malathion. At the recommended application rate (10 ppm), with the exception of indol acetic acid and treflan, all compounds suppressed mold growth and aflatoxin production.

Hill-Activity and P700 Concentration of Chloroplasts Isolated from Radish Seedlings Treated with -Indoleacetic Acid, Kinetin or Gibberellic Acid

1977 ◽  
Vol 32 (9-10) ◽  
pp. 798-802 ◽  
Author(s):  
Claus Buschmann ◽  
Hartmut K. Lichtenthaler
Keyword(s):  
Steady State ◽  
Gibberellic Acid ◽  
Photosynthetic Activity ◽  
Indoleacetic Acid ◽  
Photosynthetic Apparatus ◽  
Promotion Effect ◽  
Hill Activity ◽  
The Hill ◽  
Radish Seedlings ◽  
Very High

Abstract The Hill-activity (reduction of DCPIP or methylviologen) and the concentration of P700 were studied in chloroplasts isolated from cotyledons of radish seedlings (R aphanus sativu s L. Saxa Treib), which had been grown with the addition of β-indoleacetic acid (IAA), kinetin, or gibberellic acid.1) The photosynthetic activity of young chloroplasts from 3 day old Raphanus seedlings is very high (c. 180 μmol O2/mol chlorophyll × h) and decreases continuously thereafter with increasing age. The steady state Hill-activity is readied after 8 to 10 days (values of 55 to 50 μmol 02/mg chlorophyll × h).2) Chloroplasts from plants treated with IAA or kinetin not only exhibit higher plastoquinone levels 1,2, but also a higher P700-content and a higher Hill-activity. The promotion effect is more pronounced with kinetin (+ 36 to 40%) than with IAA (+ 12 to 17%).3) Gibberellic acid has a different effect on composition and activity of chloroplasts. In younger seedlings the Hill-activity appears to be somewhat stimulated, without promotion effect on plasto­ quinone 2 or P700 concentration. After 10 days GA3-treated plants show signs of chlorosis combined with a strong decrease in photosynthetic activity.4) The data clearly demonstrate that the composition and activity of the photosynthetic ap­ paratus are under phytohormone control. IAA and even better kinetin promote the light induced formation of pigment systems and electrontransport chains. GA3 seems to block the rebuilding of the photosynthetic apparatus under steady state conditions.

Increase of indoleacetic acid oxidase isoenzymes by gibberellic acid in tobacco callus cultures

1971 ◽  
Vol 49 (5) ◽  
pp. 687-693 ◽  
Author(s):  
T. T. Lee
Keyword(s):  
Gibberellic Acid ◽  
Indoleacetic Acid ◽  
Polyacrylamide Gel Electrophoresis ◽  
Callus Cultures ◽  
Tobacco Callus ◽  
Acid Oxidase ◽  
Iaa Oxidase ◽  
Characteristic Type ◽  
Indoleacetic Acid Oxidase ◽  
Callus Tissues

Indoleacetic acid (IAA) oxidase in tobacco callus tissues (Nicotiana tabacum L., cultivar White Gold) grown on a medium supplemented with gibberellic acid (GA3), IAA, and kinetin was resolved into seven isoenzymes by polyacrylamide gel electrophoresis. Gibberellic acid promoted the development of three fast-migrating IAA oxidase isoenzymes which were 7- to 10-fold more active than those of the control. Gibberellic acid was effective at 2 × 10−9 M and its activity increased with increasing concentration up to 2 × 10−7 M. Actinomycin D and cycloheximide inhibited the development of these isoenzymes, suggesting a requirement for both RNA and protein synthesis. The GA3-promoted IAA oxidase isoenzymes increased with time and were positively associated with the GA3-induced characteristic type of growth.The expression of the GA3 effect on IAA oxidase isoenzymes and growth was dependent on IAA and kinetin. In the presence of appropriate concentrations of kinetin, the combined effect of GA3 and IAA was more than additive. A possible interpretation of the GA3–IAA interaction is discussed.

Plant hormones-III. Identification of gibberellic acid in immature barley and immature grass

1963 ◽  
Vol 2 (4) ◽  
pp. 307-314 ◽  
Author(s):  
D.F. Jones ◽  
J. Macmillan ◽  
M. Radley
Keyword(s):  
Gibberellic Acid ◽  
Plant Hormones

scholarly journals A CENH3 mutation promotes meiotic exit and restores fertility in SMG7-deficient Arabidopsis

2021 ◽  
Author(s):  
Claudio Capitao ◽  
Sorin Tanasa ◽  
Jaroslav Fulnecek ◽  
Vivek Kumar Raxwal ◽  
Svetlana Akimcheva ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Growth And Development ◽  
Histone H3 ◽  
Wild Plants ◽  
Pollen Production ◽  
Plant Growth And Development ◽  
Apparent Effect ◽  
Viable Pollen ◽  
Mother Cells ◽  
Suppressor Screen

Meiosis in angiosperm plants is followed by mitotic divisions to form multicellular haploid gametophytes. Termination of meiosis and transition to gametophytic development is, in Arabidopsis, governed by a dedicated mechanism that involves SMG7 and TDM1 proteins. Mutants carrying the smg7-6 allele are semi-fertile due to reduced pollen production. We found that instead of forming tetrads, smg7-6 pollen mother cells undergo multiple rounds of chromosome condensation and spindle assembly at the end of meiosis, resembling aberrant attempts to undergo additional meiotic divisions. A suppressor screen uncovered a mutation in centromeric histone H3 (CENH3) that increased fertility and promoted meiotic exit in smg7-6 plants. The mutation led to inefficient splicing of the CENH3 mRNA and a substantial decrease of CENH3, resulting in smaller centromeres. The reduced level of CENH3 delayed formation of the mitotic spindle but did not have an apparent effect on plant growth and development. We suggest that impaired spindle re-assembly at the end of meiosis limits aberrant divisions in smg7-6 plants and promotes formation of tetrads and viable pollen. Furthermore, the reduced level of CENH3 did not induce haploid plants in crosses with wild plants, indicating that differences in centromere size is not the key determinant of centromere-mediate genome elimination.

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