Response of Barley Shoot Apices to Application of Gibberellic Acid: Initial Response Pattern.

1978 ◽  
Vol 5 (3) ◽  
pp. 311 ◽  
Author(s):  
PB Nicholls
Keyword(s):  
Gibberellic Acid ◽  
Response Pattern ◽  
Initial Response ◽  
Leaf Primordia ◽  
Controlled Environment ◽  
Hordeum Vulgare L ◽  
Morphological Response ◽  
Short Period ◽  
Rates Of Growth ◽  
Short Days

Seedlings of barley (Hordeum vulgare L. cv. Clipper) were grown in either controlled-environment chambers or in a frost-free glasshouse in short days and were treated with aqueous gibberellic acid solutions at the 1½-leaf stage. A single application of gibberellic acid resulted in enhanced rates of growth of the apex and subjacent leaf primordia for only a relatively short period in the life cycle of the plant. The first morphological response to the treatment was an increased dome length, which was followed by increased rates of growth and development of subjacent leaf primordia and basal spikelet primordia. After the period of enhancement, the growth rates of the apices of the treated plants fell to values comparable to those of the control plants.

Ontogeny and histochemistry of the intermediate and reproductive apices of Cosmos bipinnatus var. Sensation in response to gibberellin A3 and photoperiod

1973 ◽  
Vol 51 (3) ◽  
pp. 535-551 ◽  
Author(s):  
Marje Molder ◽  
John N. Owens
Keyword(s):  
Gibberellic Acid ◽  
Response Rate ◽  
Intermediate Stage ◽  
Floral Initiation ◽  
Transitional Stage ◽  
Zonation Pattern ◽  
Short Day ◽  
Cosmos Bipinnatus ◽  
Cytological Features ◽  
Short Days

Plants of Cosmos bipinnatus Cav. ‘Sensation’ (a quantitative short-day plant) were grown under continuous conditions favorable or unfavorable for flowering, and some plants in each group were treated with gibberellic acid (GA3). Floral apices of Cosmos are formed by the transition of previously vegetative apices. The vegetative apex shows a cytohistological zonation pattern superimposed upon a tunica–corpus organization. The vegetative apex passes into an intermediate stage presumed typical of many plants held under non-inductive conditions. This stage is marked by many cytological features characteristic of both reproductive and vegetative apices but leaves continue to be produced. The presence of the intermediate stage accounts for conflicting results obtained in physiological studies since there is great variation in response rate depending on age of plant and the stage of the apex at the start of an experiment. This stage is followed by a typical transitional stage marked by an increase in RNA content, increased mitotic activity, and a change in zonation. Elongation of the apex and internodes occurs followed by initiation of the involucral bracts and floret primordia, marking the beginning of the prefloral and inflorescence stages respectively.GA3 specifically induces Cosmos to flower under non-inductive conditions thereby influencing floral initiation in a facultative short-day plant. Microscopic examination of the rate of apical transition revealed that GA3 substituted effectively for short days but was not as efficient an inducer as were short days.

Biology of Brassica tournefortii in the northern grains region of Australia

2020 ◽  
Vol 71 (3) ◽  
pp. 268
Author(s):  
Gulshan Mahajan ◽  
Rajandeep Singh ◽  
Bhagirath S. Chauhan
Keyword(s):  
Soil Depth ◽  
Integrated Management ◽  
Management Strategies ◽  
Burial Depth ◽  
Hordeum Vulgare L ◽  
Tillage Systems ◽  
No Till ◽  
Short Period ◽  
Buried Seeds ◽  
Brassica Tournefortii

Brassica tournefortii Gouan. (wild turnip, WT) has become a problematic weed in the no-till production systems of the northern grains region of Australia. Experiments were undertaken using different biotypes of B. tournefortii to examine its phenology, emergence and seedbank persistence. Biotypes were obtained from paddocks of barley (Hordeum vulgare L.) (WT1 and WT9) and chickpea (Cicer arietinum L.) (WT1/17 and WT2/17). Fresh seeds initially had high dormancy rates and persisted for a short period on the surface. Seedbank persistence increased with burial depth, with 39% of seeds remaining for WT1 and 5% for WT9 after 30 months at 2 cm depth. Persistence of buried seeds varied across biotypes; WT1/17 seedlings also emerged in the second growing season from 2 cm depth. Compared with buried seeds, seedlings readily emerged from the surface (in March–June following increased rainfall) within 6 months of planting. Emergence was greatest on the surface and varied between biotypes and tillage systems; the highest rate recorded was ~14%. Multiple cohorts were produced between February and October. No-till systems produced higher emergence rates than conventional tillage systems. Seedlings of B. tournefortii did not emerge from 5 cm soil depth; therefore, diligent tillage practices without seedbank replenishment could rapidly reduce the presence of this weed. A soil-moisture study revealed that at 25% of water-holding capacity, B. tournefortii tended to produce sufficient seeds for reinfestation in the field. Brassica tournefortii is a cross-pollinated species, and its wider emergence time and capacity to produce enough seeds in a dry environment enable it to become widespread in Australia. Early cohorts (March) tended to have vigorous growth and high reproduction potential. This study found B. tournefortii to be a poor competitor of wheat (Triticum aestivum L.), having greater capacity to compete with the slow-growing crop chickpea. Therefore, control of early-season cohorts and use of rotations with a more vigorous crop such as wheat may reduce the seedbank. The information gained in this study will be important in developing better understanding of seed ecology of B. tournefortii for the purpose of developing integrated management strategies.

Dormancy regulation: hormonal interaction in maple (Acer platanoides)

1969 ◽  
Vol 47 (7) ◽  
pp. 1165-1169 ◽  
Author(s):  
A. E. DeMaggio ◽  
J. A. Freeberg
Keyword(s):  
Abscisic Acid ◽  
Gibberellic Acid ◽  
Acid Treatment ◽  
Acer Platanoides ◽  
Sterile Culture ◽  
Hormonal Interaction ◽  
Bud Growth ◽  
Short Days ◽  
Gibberellic Acid Treatment

Whole buds and excised apices (bud scales removed) from dormant trees of Acer platanoides grow in sterile culture in long days but have different responses to gibberellic acid treatment. Bud growth is stimulated by the hormone in long and short days but apices are unaffected. Abscisic acid inhibits not only gibberellin-stimulated bud growth but also the photoperiodically stimulated growth of apices.

Successful Desensitization to Oxaliplatin

2005 ◽  
Vol 39 (5) ◽  
pp. 966-969 ◽  
Author(s):  
Lydia ◽  
Nishan H Fernando ◽  
Hurbert I Hurwitz ◽  
Michael A Morse
Keyword(s):  
White Woman ◽  
Initial Response ◽  
Response To Therapy ◽  
Controlled Environment ◽  
Metastatic Colon Cancer ◽  
Hypersensitivity Reactions ◽  
Platinum Compounds ◽  
Probability Scale ◽  
Case Summary ◽  
Life Threatening

OBJECTIVE: To report the successful desensitization of a patient to oxaliplatin utilizing an 8-hour desensitization regimen in a controlled environment. CASE SUMMARY: A 53-year-old white woman with metastatic colon cancer was receiving oxaliplatin, bevacizumab, and capecitabine every 2 weeks, with a partial response to therapy. On her fifth cycle of this regimen, she experienced diaphoresis, hypotension, nausea, abdominal cramping, and coryza. According to the Naranjo probability scale, oxaliplatin, and not bevacizumab, was the probable cause of the hypersensitivity reaction. The woman continued therapy with capecitabine and bevacizumab, resulting in stable disease. Due to her initial response to the oxaliplatin-based regimen, it was decided to attempt desensitization to oxaliplatin in a controlled, inpatient environment. An 8-hour desensitization schedule was employed, and the patient successfully completed an additional 3 cycles with full-dose oxaliplatin. DISCUSSION: Hypersensitivity reactions to platinum-containing compounds are well described and potentially life threatening. With expanded use of oxaliplatin in various malignancies, an increased number of hypersensitivity reactions will likely be reported. Patients with previous hypersensitivity reactions to carboplatin are at risk for similar reactions to oxaliplatin. We achieved successful desensitization for oxaliplatin using increased concentrations of the drug over an 8-hour period concomitant with oral and intravenous corticosteroids and histamine blockers. CONCLUSIONS: Hypersensitivity reactions to platinum compounds may result in discontinuation of active therapies in patients with metastatic disease. Desensitization to oxaliplatin is possible utilizing this approach.

Leaf development in two-row spring barley under long-day and short-day field conditions

2004 ◽  
Vol 84 (2) ◽  
pp. 477-486 ◽  
Author(s):  
B. H. Paynter ◽  
P. E. Juskiw ◽  
J. H. Helm
Keyword(s):  
Hordeum Vulgare ◽  
Western Australia ◽  
Spring Barley ◽  
Linear Regression Analysis ◽  
Leaf Number ◽  
Hordeum Vulgare L ◽  
Short Day ◽  
Leaf Emergence ◽  
Long Day ◽  
Short Days

To gain an understanding of the adaptation of Australian and Canadian barley (Hordeum vulgare L.) cultivars to the environments of western Canada and Western Australia, phyllochron and number of leaves on the mainstem in eight cultivars of two-row, spring barley were examined when sown at two dates in two locations. The locations were a short-day environment at Northam, Western Australia, Australia in 1997 and a long-day environment at Lacombe, Alberta, Canada in 1998. At each location highly significant relationships between leaf number on the mainstem and thermal time were found (r2 > 0.94). Using linear estimates, the phyllochron of barley under short days was longer than under long days and was correlated to time to awn emergence. Later sowing shortened phyllochron under short days, but generally not under long days. Error messages from the linear regression analysis suggested that residuals were not random for all cultivars. Bilinear models were fitted to those datasets. Bilineal responses were observed under both short and long days, being independent of cultivar, date of seeding, final leaf number, phenological development pattern and time to awn emergence. The occurrence of a bilinear response was also independent of any ontogenetic events. The change in phyllochron occurred between leaves 4–7 at Northam and between leaves 6–9 at Lacombe. The leaf number at which the phyllochron change occurred was positively related to final leaf number and time to awn emergence. The phyllochron of early forming leaves was positively related to time to awn emergence and shorter than later forming leaves. Leaf emergence patterns in spring barley under both long-day and short-day conditions may therefore be linear or bilinear. Key words: barley (spring), Hordeum vulgare L., phyllochron, leaf emergence, daylength

scholarly journals Some 'high sugar grasses' don't like it hot

2004 ◽  
pp. 265-271 ◽  
Author(s):  
A.J. Parsons ◽  
S. Rasmussen ◽  
H. Xue ◽  
J.A. Newman ◽  
C.B. Anderson ◽  
...  
Keyword(s):  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Quality Trait ◽  
Controlled Environment ◽  
High Sugar ◽  
Series Of Experiments ◽  
High Concentrations ◽  
The Uk ◽  
And Control ◽  
Short Days

Cultivars of Lolium perenne with high concentrations of water soluble carbohydrates (WSC) are seen as desirable for the reduction of nitrogen losses and greenhouse gases (notably N2O) produced from grazing by livestock, as well as offering some opportunities for increasing meat and milk production. These benefits have been shown consistently in the UK, but here we report a series of investigations which suggest the high sugar grass (HSG) trait may not be so consistently or readily expressed in field conditions in New Zealand. First, the cultivars AberDart (HSG) and Fennema (control) were grown in paddocks in the Manawatu (Aorangi) and studied from July 2001 to October 2002. Total WSC levels in the harvestable component (leaf snips) increased during spring in both cultivars, but the differences between the HSG and control were smaller than seen in the UK and were only marginally significant (P = 0.063). Likewise, no consistent differences in WSC in leaf blades were found in a second trial, grown this time in pots outdoors, where water and nutrients were more controlled. This second trial included not just AberDart, but the original HSG, AberDove, which had been the focus of many successful trials in the UK. An analysis of the environmental factors that might be relevant to the expression of the quality trait 'high sugar', and of possible differences between UK and NZ climates and trials, led us to a third series of experiments, conducted in NZ, in controlled environment chambers. Total WSC became substantially greater (> 2fold) in all three cultivars when grown at 10oC (day and night) than at 20oC but only at 10 oC did one HSG, AberDove, show a small, but significantly greater WSC, than Fennema (P < 0.05). However, significantly higher levels of WSC (P < 0.05) were expressed in leaf blades of both AberDart and AberDove, compared to Fennema, when grown at temperatures of 20oC day / 10oC night (14h day), and especially (68% and 46% respectively) when this followed a period of cold (10 weeks at 5oC) and short days. Our findings suggest that low temperatures, either low night temperatures, or previous periods of sustained cold (

scholarly journals Cultivar, Photoperiod, and Gibberellin Influence Shoot Elongation and Photosynthetic Capacity of Hardy Azaleas

HortScience ◽  
1995 ◽  
Vol 30 (2) ◽  
pp. 257-259
Author(s):  
David J. Ballantyne
Keyword(s):  
Gibberellic Acid ◽  
Photosynthetic Capacity ◽  
Shoot Elongation ◽  
Greenhouse Experiment ◽  
High Rate ◽  
Production Time ◽  
Time Period ◽  
Short Days

In a greenhouse experiment involving 13 hardy azalea (Rhododendron spp.) cultivars, `Noordthiana' and `Treasure' had the highest rate of shoot elongation and the highest photosynthetic capacity (Pcap) during the summer. In winter, `Treasure' had a high rate of shoot elongation and Pcap, but `Noordthiana' had a high rate of shoot elongation and low Pcap. Long days or GA3 sprays stimulated shoot elongation but not Pcap of certain cultivars. GA3 was effective in stimulating shoot elongation of `Vuyk's Scarlet' if plants were given supplemental photoperiods under natural winter (short) photoperiods. Cultivars with a high rate of shoot elongation and Pcap likely will produce salable plants in a shorter time period than slower growing cultivars because less time elapses between prunings. Production time can be decreased further with GA3 sprays, especially with GA3 applications in combination with supplemental photoperiods during the short days of winter. Chemical name used: gibberellic acid (GA3).

scholarly journals Photoperiod and Gibberellic Acid Modify Growth and Flowering of Craspedia Globosa

HortScience ◽  
1992 ◽  
Vol 27 (10) ◽  
pp. 1082-1084
Author(s):  
David C. Annis ◽  
Paul T. Gibson ◽  
Terri Woods Starman
Keyword(s):  
Gibberellic Acid ◽  
Dicarboxylic Acid ◽  
Foliar Sprays ◽  
Total Plant ◽  
Application Frequency ◽  
Secondary Inflorescence ◽  
Short Days

The objective of this study was to investigate the influence of photoperiod and 0, 1, 5, or 10 applications at weekly intervals of GA3 foliar sprays at 500 mg·liter–1 on growth and flowering of Craspedia globosa `Drumstick' Benth. Long days (LD) hastened flowering and increased the number of flowers per plant. Short days (SD) increased foliage height and foliage fresh and dry weights. Foliage and total plant heights increased and days to bud and secondary inflorescence width decreased linearly as GA3 application frequency increased. Chemical name used: (1α,2β,4aα,4bβ,10β)-2,4a,7-trihydroxy-1-methyl-8-methylen egibb-3-ene-1,10-dicarboxylic acid 1,4a-lactone (gibberellic acid, GA3).

Response of Barley Shoot Apices to Application of Gibberellic Acid and Abscisic Acid: Dependence on Tissue Sensitivity

1978 ◽  
Vol 5 (5) ◽  
pp. 581 ◽  
Author(s):  
PB Nicholls
Keyword(s):  
Abscisic Acid ◽  
Gibberellic Acid ◽  
Acid Treatment ◽  
Apical Meristem ◽  
Internode Elongation ◽  
Shoot Apices ◽  
Tissue Sensitivity ◽  
Short Days ◽  
Gibberellic Acid Treatment ◽  
Acid Dependence

Stimulation by gibberellic acid of rachis internode elongation in barley grown in short days was dependent on either the timing of application or on the amount applied in a dose at day 10. There was no immediate rachis internode elongation in response to gibberellic acid treatment until floret initials appeared and then only if sufficient gibberellic acid was present in the shoot apices of the barley plants grown in short days. Applications of gibberellic acid promoted the growth of the double-ridge meristem (upper ridge only) and this resulted in a group of abnormal spikelets being formed on the lower six nodes of the inflorescence, all of which were characterized by enhanced growth of the rachilla apical meristem. In a 2 × 2 factorial experiment with gibberellic acid, abscisic acid was found to slightly reduce the growth rate of the vegetative barley apex between days 10 and 14. Abrupt cessation of primordium formation, coincident with the appearance of stamen initials, was observed following continued application of both gibberellic acid and abscisic acid whereas neither hormone alone had this effect. Enhanced growth of the rachilla apical meristem of the basal six spikelets following application of gibberellic acid resulted in the formation of branched inflorescences, and this result was not altered by the addition of abscisic acid to the treatment.

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