Regulation in Lolium temulentum of the Metabolism of Gibberellin A20 and Gibberellin A1 by 16,17-Dihydro GA5 and by the Growth Retardant, LAB 198 999

1997 ◽  
Vol 24 (3) ◽  
pp. 359 ◽  
Author(s):  
O. Junttila ◽  
R.W. King ◽  
A. Poole ◽  
G. Kretschmer ◽  
R.P. Pharis ◽  
...  
Keyword(s):  
Growth Retardation ◽  
Higher Plants ◽  
Shoot Elongation ◽  
Stem Growth ◽  
Growth Retardant ◽  
Shoot Tips ◽  
Stem Tissue ◽  
Lolium Temulentum ◽  
Gibberellin A1 ◽  
Excised Tissue

The ring D-modified gibberellin [GA], 16,17-dihydro GA5, can retard stem growth in Lolium temulentum L. while promoting flowering (Evans et al., 1994, Planta193, 107–114). Using [1,2,3-3 H]GA20 to study the final biosynthetic step to GA1 (a known effector of shoot elongation in higher plants), it was shown that C-3b-hydroxylation of GA20 to GA1 is blocked by 16,17-dihydro GA5 but is little affected by GA5. Another late-stage biosynthetic inhibitor, the acylcyclohexanedione, LAB 198 999, also blocked GA1 formation. Furthermore, endogenous levels of GA20 built up after application of 16,17-dihydro GA5. Consequently, growth retardation by 16,17-dihydro GA5 and LAB 198 999 is likely to be the result of their inhibition of GA20 3b-hydroxylation to GA1. Another fate for GA20 in Lolium is its C-2b-hydroxylation to growth-inactive GA29. This conversion was also inhibited by 16,17-dihydro GA5 but less so by LAB 198 999. The analogous step involving 2b-hydroxylation of GA1 to GA8 appeared to be insensitive to either growth retardant. When [3H]GA20 was injected into the cavity within the young intact sheathing leaves, there was an appreciable metabolism of this GA20 to GA1 and thence to GA8 (ca 10% and 30% respectively within 5 h). For excised shoot tips, however, [3H]GA20 was converted rapidly and virtually completely to GA29 in 3–5 h. Interestingly, with these excised shoot tips, GA3 and GA5 as well as 16,17-dihydro GA5 when applied via the agar strongly inhibited 2b-hydroxylation of GA20 to GA29. In contrast, while 16,17-dihydro GA5 blocked GA20 metabolism to GA29 in intact sheath/stem tissue, this conversion was not inhibited by GA5. These differences in structural specificity for GAs which inhibit 2b-hydroxylation as opposed to 3b-hydroxylation are in accordance with these two Ring-A hydroxylation steps being catalysed by different enzymes. Finally, the differences in GA20 metabolism between intact versus excised tissue raise the possibility that tissue wounding with excision enhanced the activity of the GA20 2b-hydroxylase(s).

Structural analysis of oligomeric fructans from excised leaves of Lolium temulentum

2020 ◽  
Author(s):  
Ian Sims ◽  
CJ Pollock ◽  
R Horgan
Keyword(s):  
Mass Spectrometry ◽  
Structural Analysis ◽  
Higher Plants ◽  
Water Soluble ◽  
Lolium Temulentum ◽  
Neutral Water ◽  
Alditol Acetates ◽  
Partially Methylated

Individual fructan tri-, tetra- and pentasaccharide isomers in neutral, water-soluble extracts from Lolium temulentum were purified and the linkages present in these isomeric oligosaccharides were analysed by combined GC-mass spectrometry of partially methylated alditol acetates. 1-Kestose and neokestose were the most abundant trisaccharides with 6-kestose present in much lower amounts. Analysis of isomers of DP 4 and 5 showed that multiple linkage types were present with structures based on all three trisaccharides. Oligosaccharides based on neokestose but with 2,6 linkages between adjacent fructose residues have not been previously detected in higher plants. © 1992.

scholarly journals In Vitro Micropropagation of Orchid (Vanda tessellata L.) from Shoot Tip Explant

1970 ◽  
Vol 17 ◽  
pp. 139-144 ◽  
Author(s):  
MS Rahman ◽  
MF Hasan ◽  
R Das ◽  
MS Hossain ◽  
M Rahman
Keyword(s):  
Multiple Shoots ◽  
Shoot Elongation ◽  
Shoot Formation ◽  
Multiple Shoot ◽  
Shoot Tips ◽  
Shoot Tip ◽  
Root Induction ◽  
Ms Medium ◽  
Culture Techniques

Context: Orchid produces a huge number of minute seeds but the seeds can not germinate easily in nature due to the lack of endosperm in the seeds is an incompatibility barrier that limits its propagation in nature. Objectives: To develop in vitro culture techniques for quick propagation of Vanda tessellate, a commercially important orchid species. Materials and Methods: Shoot tips were used as experimental materials. The explants were surface sterilized and the shoot tips were excised. The isolated shoot tips were cultured in MS medium supplemented with different concentration and combinations of auxin and cytokinin. Results: The combination of 1.5 mgl-1 NAA and 1.0 mgl-1 BAP was proved to be the best medium formulation for multiple shoot formation as well as maximum shoot elongation. The single shoots were isolated from the multiple shoots and subcultured in MS medium having NAA and IBA individually and in combinations for root induction. Maximum root induction was obtained in MS agarified medium having 0.5 mgl-1NAA and 1.0 mgl-1IBA. The well rooted plantlets were hardened successfully in the potting mixture containing coconut husk, perlite, charcoal, brick pieces in the ratio of 2:1:1:1 and eventually established under natural condition.Conclusion: An efficient regeneration protocol for micropropagation in V. tessellata through shoot tip culture has been established.Key words: Shoot tip; micropropagation; orchid.DOI: 10.3329/jbs.v17i0.7122J. bio-sci. 17: 139-144, 2009

The Acceleration of Primordium Initiation as a Component of Floral Evocation in Lolium temulentum L

1996 ◽  
Vol 23 (5) ◽  
pp. 569 ◽  
Author(s):  
LT Evans ◽  
C Blundell
Keyword(s):  
Shoot Apex ◽  
Floral Development ◽  
Growth Retardant ◽  
Leaf Primordium ◽  
Essential Component ◽  
Lolium Temulentum ◽  
Long Day ◽  
External Sign ◽  
Floral Evocation

An acceleration of leaf primordium initiation by the shoot apex frequently follows floral evocation, but after varying intervals. The purpose of the experiments reported here was to define more closely the relation between this reduction of the plastochron and floral evocation, using the long day (LD) plant Lolium temulentum grown under closely controlled conditions.The acceleration begins at floral evocation, on the day after the first LD exposure, and increases after exposure to additional LDs. However, plants too young to be florally evoked by one LD nevertheless manifested an acceleration of primordium initiation, so the acceleration alone is not sufficient for evocation. Single applications of highly florigenic gibberellins (GAs), such as GA5, also accelerate the initiation of primordia and floral development, more so than does the weakly florigenic GA1. By contrast, single applications of the growth retardant Trinexapac-ethyl (CGA 163'935) to plants given one LD largely prevented the acceleration of primordium initiation but without inhibiting floral development. Thus, although the acceleration of primordium initiation by LD or by GA application is the first external sign of floral evocation in L. temulentum, it is neither a sufficient nor an essential component of it.

scholarly journals (94) Efficacy of Application Methods and Concentration of Plant Growth Retardants on Growth of Chrysanthemum (Dendranthem ×grandiflorum `Cheasepeake')

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1046A-1046
Author(s):  
Chun Ho Pak ◽  
Seung Won Kang ◽  
Chiwon W. Lee
Keyword(s):  
Plant Growth ◽  
Plant Height ◽  
Nutrient Solution ◽  
Growth Retardation ◽  
Growth Retardant ◽  
Plant Production ◽  
Growth Retardants ◽  
Total Plant ◽  
Plant Growth Retardants ◽  
Application Methods

Efficacy of application methods and concentration of plant growth retardants on growth of chrysanthemum (Dendranthema ×grandiflorum cv. Cheasepeake) was tested. B-9 or cycocel (CCC) as a growth retardant was applied as drench or subapplication with nutrient solution. In the case of B-9 drench treatments, as B-9 concentrations increased, numbers of flowers and flower buds increased except in the 1500-ppm treatment. Increasing concentration of CCC also resulted in reduction of flower numbers, total plant height, total leaf area, branch number, and fresh weight. Reduction ratio of total plant height in 2000 ppm showed about 56.9% being compared to that of the 100-ppm drench treatment. B-9 or CCC, combined with nutrient solution, was also supplied from the C-channel subirrigation system. The B-9 subapplication treatment showed no significance among these concentrations, but flower numbers, total plant height, average plant height, and leaf numbers decreased as concentrations of CCC increased. B-9 or CCC with the same concentration was drenched after 2 weeks of the first experiment to compare planting time efficacy. Measured data increased until B-9 increased up to 2500 ppm and severe growth retardation resulted from the 5000-ppm treatment. Through this growth retardant application study, the combination of drenching concentration and period of plant growth regulators (PGRs) may result in effective growth retardation and reduction of application concentrations for pot plant production.

Distribution of physiologically inactive zinc in maize growing on a black earth soil

1978 ◽  
Vol 29 (4) ◽  
pp. 749 ◽  
Author(s):  
DR Leece
Keyword(s):  
Zinc Deficiency ◽  
Stem Growth ◽  
Stem Tissue ◽  
Maize Seedlings ◽  
High Zinc ◽  
Zinc Concentrations ◽  
Low Levels ◽  
Very High

Physiologically inactive zinc occurred in the roots and leaves but not the stems of maize seedlings when grown for 30 days in pots on a black earth soil. Expanded leaves had very high zinc concentrations (60–200 µg/g), yet expressed symptoms of zinc deficiency, which indicated that most of the zinc in these tissues was inactive. By contrast, stem tissue, which was 36% leaf sheaths and 64% new leaves and meristems, contained low levels of zinc (17 µg/g) when unfertilized and normal levels (27 µg/g) when fertilized with 10 µg/g zinc. Stem growth indicated that this zinc was active. Fertilizer phosphorus (200 µg/g) induced phosphorus/zinc imbalance and inactivated zinc further in roots, certain expanded leaves, and the stem. Zinc and phosphorus deficiencies and zinc inactivation were prevented by fertilization with both zinc (10 µg/g) and phosphorus (200 µg/g). This system is proposed as a model for the study of chemical and biochemical forms of active and inactive zinc in maize.

scholarly journals Production and leaf plasticity of rose plants sprayed with paclobutrazol and daminozide

2017 ◽  
Vol 38 (6) ◽  
pp. 3481
Author(s):  
Maristela Pereira Carvalho-Zanão ◽  
José Antônio Saraiva Grossi ◽  
Luiz Antônio Zanão Júnior ◽  
Marília Contin Ventrella ◽  
Natália Pereira
Keyword(s):  
Leaf Area ◽  
Leaf Blade ◽  
Higher Plants ◽  
Leaf Tissue ◽  
Growth Retardant ◽  
Leaf Epidermis ◽  
Palisade Parenchyma ◽  
Flower Diameter ◽  
Leaf Plasticity ◽  
Treatment Design

The aim of this work was to evaluate morphological and anatomical alterations in leaves of ‘Yellow Terrazza’® and ‘Red White Terrazza’® pot roses sprayed with paclobutrazol (0, 40, 60, 80 mg L-1) and daminozide (0, 2000, 4000, 6000, 8000 mg L-1). The experiments were conducted under greenhouse conditions using a factorial treatment design (cultivars x growth retardant doses) with five replications and experimental units arranged in randomized blocks. Cv. Yellow Terrazza ® presented higher plants, greater floral diameter and leaf area than cv. Red White Terrazza ®. Plant height, leaf area, and flower diameter decreased linearly with paclobutrazol and daminozide doses. In addition, paclobutrazol and daminozide applications changed leaf tissue proportions by increasing the thickness of leaf blade, mesophyll, palisade parenchyma, and spongy parenchyma but did not influence the thickness of leaf epidermis.

scholarly journals WHIRLY1 of barley and maize share a PRAPP motif conferring nucleoid compaction

2020 ◽  
Author(s):  
Svenja Oetke ◽  
Axel J. Scheidig ◽  
Karin Krupinska
Keyword(s):  
Arabidopsis Thaliana ◽  
Growth Retardation ◽  
Sequence Variation ◽  
Higher Plants ◽  
Specific Function ◽  
Terminal Part ◽  
E Coli ◽  
The Family ◽  
N Terminus ◽  
Poaceae Family

ABSTRACTWHIRLY1 in barley was shown to be a major architect of plastid nucleoids. Its accumulation in cells of E. coli coincided with an induction of nucleoid compaction and growth retardation. While WHIRLY1 of maize had similar effects on E. coli cells, WHIRLY1 proteins of Arabidopsis and potato a well as WHIRLY2 proteins had no impact on nucleoid compaction in E. coli. By mutagenesis of HvWHIRLY1 the PRAPP motif at the N-terminus preceding the highly conserved WHIRLY domain was identified to be responsible for the nucleoid compacting activity of HvWHIRLY1 in bacteria. This motif is found in WHIRLY1 proteins of most members of the Poaceae family, but neither in the WHIRLY2 proteins of the family nor in any WHIRLY protein of eudicot species such as Arabidopsis thaliana. This finding indicates that a subset of the monocot WHIRLY1 proteins has acquired a specific function as nucleoid compacters by sequence variation in the N-terminal part preceding the conserved WHIRLY domain and that in different groups of higher plants the compaction of nucleoids is mediated by other proteins.

scholarly journals Validation of a Model for Simulating the Effect of Daminozide Application on Chrysanthemum

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 500C-500
Author(s):  
J.H. Lieth ◽  
L.R. Oki ◽  
P. Ng ◽  
M.C. Garcia-Navarro ◽  
S.H. Kim ◽  
...  
Keyword(s):  
Foliar Spray ◽  
Shoot Elongation ◽  
Inhibitory Effect ◽  
Growth Retardant ◽  
Plant Production ◽  
Production Cycle ◽  
Decision Support Tools ◽  
Spray Application ◽  
Support Tools ◽  
Potted Plant

Daminozide is a growth retardant used in potted plant production as a foliar spray to inhibit shoot elongation. It has its greatest inhibitory effect immediately after application, becoming less pronounced thereafter; continued retardation is accomplished by reapplication at 7to 14-day intervals. A model for this retardation effect is useful in developing decision support tools, as well as in optimizing (perhaps minimizing) the use of this growth retardant. Such a model, as developed and described earlier, simulates the effect of a foliar spray application of daminozide at various concentrations on various days during the production cycle. The objective of this work was to validate this model for various varieties of chrysanthemum. Using the model to simulate the effect of one application of daminozide resulted in predicted plant heights very close to the observed heights for most of the varieties tested. Of four methods used to implement the multiple-application effect, two resulted in very good simulation of the observed plant heights. In summary, the model was shown to be valid for all the varieties of chrysanthemum tested.

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