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At least 793 records · Page 44Linked to original sources
PubMed2005

Molecular mapping of gibberellin-responsive dwarfing genes in bread wheat.

Opportunities exist for replacing reduced height (Rht) genes Rht-B1b and Rht-D1b with alternative dwarfing genes for bread wheat improvement. In this study, the chromosomal locations of several height-reducing genes were determined by screening populations of recombinant inbred lines or doubled haploid lines varying for plant height with microsatellite markers. Linked markers were found for Rht5 (on chromosome 3BS), Rht12 (5AL) and Rht13 (7BS), which accounted for most of the phenotypic variance in height in the respective populations. Large height differences between genotypes (up to 43 cm) indicated linkage to major height-reducing genes. Rht4 was associated with molecular markers on chromosome 2BL, accounting for up to 30% of the variance in height. Confirming previous studies, Rht8 was linked to markers on chromosome 2DS, whereas a population varying for Rht9 revealed a region with a small but significant height effect on chromosome 5AL. The height-reducing effect of these dwarfing genes was repeatable across a range of environments. The molecular markers developed in this study will be useful for marker-assisted selection of alternative height-reducing genes, and to better understand the effects of different Rht genes on wheat growth and agronomic performance.

Bread↗
PubMed2004

A rapid response of beta-amylase to nitric oxide but not gibberellin in wheat seeds during the early stage of germination.

The effects of nitric oxide (NO) and gibberellic acid (GA(3)) on the responses of amylases in wheat (Triticum aestivum L.) seeds (caryopses) were investigated during the first 12 h of germination. GA(3) had no effects on the activities of alpha-amylase (EC 3.2.1.1) or beta-amylase (EC 3.2.1.2), either in intact seeds or embryoless halves within 12 h. In contrast, addition of sodium nitroprusside (SNP), an NO donor, was able to induce a rapid increase in beta-amylase activity without affecting alpha-amylase. Furthermore, the rapid response of beta-amylase to SNP in wheat seeds could be attributed to NO and was approximately dose-dependent. Some other aspects of SNP induction of amylase isozymes were also characterized. Further investigations showed that SNP might play an interesting role in the dissociation of free beta-amylase from small homopolymers or heteropolymers. Furthermore, SNP also directly induced the release of bound beta-amylase from glutenin and its crude enzyme preparation. However, the slight increase in protease also induced by SNP might not be responsible for this action. Interestingly, based on the fact that the rapid response of beta-amylase to NO also existed in seeds of other species, such as barley, soybean, rice and watermelon, it might be a universal event in early seed germination.

Benzoates↗
PubMed2005

Auxin-cytokinin and auxin-gibberellin interactions during morphogenesis of the compound leaves of pea (Pisum sativum).

A number of mutations that alter the form of the compound leaf in pea (Pisum sativum) has proven useful in elucidating the role that auxin might play in pea leaf development. The goals of this study were to determine if auxin application can rescue any of the pea leaf mutants and if gibberellic acid (GA) plays a role in leaf morphogenesis in pea. A tissue culture system was used to determine the effects of various auxins, GA or a GA biosynethesis inhibitor (paclobutrazol) on leaf development. The GA mutant, nana1 (na1) was analyzed. The uni-tac mutant was rescued by auxin and GA and rescue involved both a conversion of the terminal leaflet into a tendril and an addition of a pair of lateral tendrils. This rescue required the presence of cytokinin. The auxins tested varied in their effectiveness, although methyl-IAA worked best. The terminal tendrils of wildtype plantlets grown on paclobutrazol were converted into leaflets, stubs or were aborted. The number of lateral pinna pairs produced was reduced and leaf initiation was impaired. These abnormalities resembled those caused by auxin transport inhibitors and phenocopy the uni mutants. The na1 mutant shared some morphological features with the uni mutants; including, flowering late and producing leaves with fewer lateral pinna pairs. These results show that both auxin and GA play similar and significant roles in pea leaf development. Pea leaf morphogenesis might involve auxin regulation of GA biosynthesis and GA regulation of Uni expression.

Benzyl Compounds↗
PubMed1987

Gibberellin-enhanced elongation of inverted Pharbitis nil shoot prevents the release of apical dominance.

Ethylene evolution resulting from the gravity stress of shoot inversion appears to induce the release of apical dominance in Pharbitis nil (L.) by inhibiting elongation of the inverted shoot. It has been previously demonstrated that this shoot inversion release of apical dominance can be prevented by promoting elongation in the inverted shoot via interference with ethylene synthesis or action. In the present study it was shown that apical dominance release can also be prevented by promoting elongation of the inverted shoot via treatment with gibberellic acid (GA3). A synergistic effect was observed when AgNO3, the ethylene action inhibitor, was applied with GA3. Both GA3 and AgNO3 increased ethylene production in the inverted shoot. These results are consistent with the view that it is ethylene-induced inhibition of elongation and not any direct effect of ethylene per se which is responsible for the outgrowth of the highest lateral bud.

Drug Synergism↗