Influence Of Growth Regulators Research Articles

Effects of growth regulators on ribonucleic acid metabolism of barley leaf segments.

Illumination or gibberellic acid treatment of etiolated barley leaf segments stimulates unrolling and results in an increased level of RNA. In contrast, segments treated with abscisic acid do not unroll and have a lower content of RNA. Gibberellic acid treatment enhanced the capacity of segments to incorporate radioactivity from (32)P-orthophosphate into all the RNA components detected by gel electrophoresis; abscisic acid greatly restricted the incorporation of precursors into all the RNA fractions. In conjunction with a changed capacity for RNA synthesis it was observed that abscisic acid-treated segments had a lowered soluble DNA-dependent RNA polymerase level in comparison to gibberellic acid-treated or illuminated segments. However, the influence of growth regulators on RNA polymerase content of the segments was associated with general effects on protein level rather than a specific effect on the synthesis of polymerase enzyme. Ribosomal preparations from gibberellic acid-treated segments had a greater percentage of polysomes and a greater capacity for amino acid incorporation in vitro into proteins than similar preparations from abscisic acid-treated segments.

The Influence of Growth Regulators and Temperature on Flowering of Seed Propagated Geraniums1

Abstract The influence of B-Nine (2500 ppm), F 529 (1250 ppm), TIBA (250 ppm), IAA (100 ppm), Ethrel (1000 ppm), Cycocel spray (1475 ppm) and soil drench (2950 ppm) were investigated on seed propagated geranium, cv. ‘Carefree Scarlet’. IAA had no effect on date of flowering, plant height or branching, but TIBA sprayed plants flowered significantly earlier and Ethrel sprays significantly delayed it. Both TIBA and Ethrel sprays reduced geranium height at flowering and stimulated branching. A Cycocel soil drench caused earlier flowering, but sprays had no effect on flowering. In growth chambers with 12-hour light periods of 75 F and 12-hour dark periods of 70 F, 60 F, or 50 F, earliest flowering was at 70 F with 5 and 15 days delays at 60 F and 50 F. The number of nodes of terminal stems at flowering increased from 14 at 70 F to 16 at 60 F and 17 at 50 F night temperatures.

The Influence of Growth Regulators and Temperature on Flowering of Seed Propagated Geraniums1

Abstract The influence of B-Nine (2500 ppm), F 529 (1250 ppm), TIBA (250 ppm), IAA (100 ppm), Ethrel (1000 ppm), Cycocel spray (1475 ppm) and soil drench (2950 ppm) were investigated on seed propagated geranium, cv. ‘Carefree Scarlet’. IAA had no effect on date of flowering, plant height or branching, but TIBA sprayed plants flowered significantly earlier and Ethrel sprays significantly delayed it. Both TIBA and Ethrel sprays reduced geranium height at flowering and stimulated branching. A Cycocel soil drench caused earlier flowering, but sprays had no effect on flowering. In growth chambers with 12-hour light periods of 75 F and 12-hour dark periods of 70 F, 60 F, or 50 F, earliest flowering was at 70 F with 5 and 15 days delays at 60 F and 50 F. The number of nodes of terminal stems at flowering increased from 14 at 70 F to 16 at 60 F and 17 at 50 F night temperatures.

Influence of Growth Regulators on Concentration of Protein and Nucleic Acids in ‘Black Corinth’ Grapes1

Abstract Vines of Vitis vinifera ‘Black Corinth’ were sprayed with 100 ppm gibberellin A3 (GA3), 50 ppm 4-chloro-phenoxyacetic acid (4-CPA), or 1000 ppm benzyladenine (BA) about 5 days after anthesis. The concentrations of protein, RNA, and DNA in the berries were measured at 0, 1, 6, 12, 24, 48, and 96 hr after treatment. In the fruits treated with GA3 or 4-CPA, protein, RNA, and DNA were markedly increased compared to untreated fruits during the first 24 hr after treatment; thereafter, concentrations did not significantly differ from those of the control berries. Fruits treated with BA, on the other hand, had significantly higher levels of these substances only at 1 and 6 hr post treatment.

Influence of Growth Regulators on Root and Shoot Characters of Onion

Context: The growth behaviour and yield of any crop plants are governed by their genetic potential, climatic conditions and the supply of nutrients. Specific control of these processes can be done by the application of plant bioregulators of natural or synthetic origin.Objectives: The aim of the present investigation was to study the effect of different plant growth regulators on root and shoot emergence, and root and shoot length of onion.Materials and Methods: Onion. var "Taherpuri" was used as plant material and four growth regulators namely GA3, Uniconazol, CCC and 2,3,6-TBA along with water as control with different concentration viz. 100, 150, 200, 250 and 300 ppm were used as treatment. Onion bulbs were placed on vials containing different doses of growth regulators. Data recorded on root and shoot emergence and their lengths after different days of setting the experiment.Results: Higher concentrations of uniconazole necessitated maximum days for root and shoot emergence whereas GA3 required minimum days. Root length decreased gradually with increasing the concentrations of all the growth regulators at different days of emergence. Higher concentrations of GA3 produced longest shoot whereas same concentrations of uniconazole produced the shortest than the lower ones at different days of emergence. The highly significant and negative correlation was found between days to root emergence and shoot length and between days to shoot emergence and shoot length but highly significant and positive correlation was found between root length and shoot length. Conclusion: GA3 required minimum days to root and shoot emergence and promote the vegetative growth of onion whereas uniconazole and CCC are retards and 2,3,6-TBA shows a little retarding effect.Key words: Growth regulators; Root and shoot characters; OnionDOI: 10.3329/jbs.v17i0.7101J. bio-sci. 17: 51-55, 2009

Cytokinins and Tuber Initiation in the Potato Solanum tuberosum L.

SEVERAL experiments have implicated the presence of a specific stimulus responsible for the initiation of tuber formation1, but there are few reports of the effect of cytokinins on the process2,3. Courduroux2 suggested that the specific tuber forming substance may be related to cytokinins but he did not demonstrate a requirement for cytokinins in tuber induction. The interplay of gibberellins and endogenous growth inhibitors in the regulation of tuber initiation is suggested by the extraction of gibberellin-like substances from plants and stolons in non-inductive conditions4. The disappearance of these substances and the appearance of inhibitors during the early stages of tuberization have also been demonstrated4,5. It has been claimed that tuber formation is initiated by high concentrations of soluble sugars at the stolon tip6, but Lovell and Booth found no correlation between sugar level in stolons and tuberization7. Exogenous applications of hormones have been confined mostly to foliar sprays or application of paste to stems. There is very little information on the influence of growth regulators on the stolons themselves. We have now demonstrated a requirement for cytokinins in the tuberization of isolated stolons in vitro.

The Influence of Growth Regulators and Plant Spacing on Sugar Content of the Nectar and Seed Production in Alfalfa (Medicago sativa L.)

The Influence of Growth Regulators and Plant Spacing on Sugar Content of the Nectar and Seed Production in Alfalfa (Medicago sativa L.)

Interaction of Plant Growth Regulators in Regeneration Processes

IN previous years much attention has been paid to the influence of growth regulators on regeneration processes, especially to the interactions of kinetin and auxin in morphogenesis of tissue cultures1. In experiments with Begonia leaves we have observed a decisive effect of auxin and kinetin on regeneration. In addition it could be shown that gibberellin profoundly affects the complex hormone system apparently controlling differentiation in higher plants.