Apical Dominance in Rhizomes of Quackgrass (Elytrigia repens): Inhibitory Effect of Scale Leaves

Weed Science ◽  
1989 ◽  
Vol 37 (5) ◽  
pp. 680-687 ◽  
Author(s):  
J. Mason Robertson ◽  
John S. Taylor ◽  
K. Neil Harker ◽  
Robert N. Pocock ◽  
Edward C. Yeung
Keyword(s):  
Apical Dominance ◽  
Inhibitory Effect ◽  
Axillary Buds ◽  
Aqueous Extracts ◽  
Leaf Removal ◽  
Initial Development ◽  
Leaf Material ◽  
Elytrigia Repens ◽  
Promotive Effect ◽  
Bud Growth

Surgical experiments were conducted on cultured five-node apical rhizome segments of quackgrass. Removal of scale leaves promoted an initial burst of growth within the axillary buds but did not support the continued growth of buds as effectively as removal of the rhizome apex. Replacement of detached scale leaves over denuded buds temporarily repressed the promotive effect of scale leaf removal. Aqueous extracts of scale leaf material inhibited apical growth in rhizome segments but did not inhibit bud growth. Anatomical sections revealed that removal of scale leaves promoted development of buds: cells enlarged, vascular tissues differentiated, and new nodes began to form within 4 days of the removal of scale leaves. It is suggested that scale leaves contribute to apical dominance by inhibiting the initial development of axillary buds.

Apical dominance in rhizomes of quackgrass, Elytrigia repens: the effect of auxin, cytokinins, and abscisic acid

1995 ◽  
Vol 73 (2) ◽  
pp. 307-314 ◽  
Author(s):  
J. S. Taylor ◽  
J. M. Robertson ◽  
K. N. Harker ◽  
M. K. Bhalla ◽  
E. J. Daly ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Acetic Acid ◽  
Abscisic Acid ◽  
Apical Dominance ◽  
Endogenous Hormones ◽  
Leaf Removal ◽  
Exogenous Hormone ◽  
Elytrigia Repens ◽  
Bud Growth ◽  
Indole 3 Acetic Acid

Experiments were designed to determine the impact of abscisic acid, indole-3-acetic acid, and cytokinins on dormancy of quackgrass (Elytrigia repens (L.) Nevski) rhizome axillary buds using exogenous hormone treatments and analysis of endogenous hormones. Exogenous hormone treatments were applied in solution or in lanolin paste to 5-node segments of rhizome with an apical tip intact or removed. Abscisic acid inhibited bud growth except at concentrations of 0.5 – 1 μg ∙ mL−1 when it stimulated growth: this appeared to be based on an inhibition of apical dominance rather than a stimulation of bud growth per se. Both indole-3-acetic acid and cytokinins stimulated bud growth, indole-3-acetic acid at concentrations of 0.5 – 5 μg ∙ mL−1 and cytokinins at higher concentrations (i.e., 10 – 100 μg ∙ mL−1). Indole-3-acetic acid also increased elongation of the buds, whereas abscisic acid and cytokinins did not. Levels of endogenous hormones were measured in bud samples: indole-3-acetic acid was quantified as its methyl ester by combined gas chromatography – mass spectrometry – selected ion monitoring; abscisic acid was quantified as its methyl ester by gas chromatography – electron capture; and cytokinins were quantified using a soybean callus bioassay. Hormone levels were generally higher in the most active buds of a 5-node section. Abscisic acid was also measured in buds 24 h after sheath leaf removal, a practice known to promote bud sprouting. Sheath leaf removal had no significant effect on abscisic acid levels. Key words: quackgrass, Elytrigia repens, auxins, abscisic acid, cytokinins, apical dominance.

Hormonal interaction in controlling apical dominance in soybeans

1971 ◽  
Vol 49 (9) ◽  
pp. 1727-1731 ◽  
Author(s):  
A. Ali ◽  
R. A. Fletcher
Keyword(s):  
Apical Dominance ◽  
Indoleacetic Acid ◽  
Inhibitory Effect ◽  
Benzyl Adenine ◽  
Intact Plants ◽  
Hormonal Interaction ◽  
Meristematic Activity ◽  
Bud Growth ◽  
Soybean Plants ◽  
Cut Surface

Growth of cotyledonary buds in soybean plants is controlled by an interaction between hormones and is dependent on age of the plant and meristematic activity of the buds. Indoleacetic acid (IAA) applied to the cut surface of decapitated 7-day-old plants does not inhibit the growth of buds which are actively undergoing mitosis. Growth is inhibited, however, when IAA is applied in combination with benzyl-adenine(BA) and this inhibitory effect is minimized by gibberellic acid (GA). In 16-day-old plants where mitosis in the buds has ceased IAA alone inhibits bud growth. In both 7- and 16-day-old decapitated plants, application of GA, alone or in combination with BA promotes growth of the buds. Inhibited buds have two peroxidase isoenzymes with pronounced activity. The activity of one of these decreases when the buds are released from dominance. Benzyladenine applied directly to inhibited buds initiates growth in 16-day-old intact plants and this growth is further enhanced when GA is applied 48 h after BA treatment. The enhanced growth by GA is prevented if 5-fluorouracil (5-FU) or 5-fluorodeoxyuridine (5-FDU) are applied before but not after the GA treatment. These results indicate that the hormones have a sequential role in releasing buds from apical dominance.

Changes in abscisic acid and indole-3-acetic acid in axillary buds of Elytrigia repens released from apical dominance

1995 ◽  
Vol 94 (1) ◽  
pp. 110-116 ◽  
Author(s):  
David W. Pearce ◽  
John S. Taylor ◽  
J. Mason Robertson ◽  
K. Neil Harker ◽  
Edward J. Daly
Keyword(s):  
Acetic Acid ◽  
Abscisic Acid ◽  
Apical Dominance ◽  
Axillary Buds ◽  
Elytrigia Repens ◽  
Indole 3 Acetic Acid

Changes in abscisic acid and indole-3-acetic acid in axillary buds of Elytrigia repens released from apical dominance

1995 ◽  
Vol 94 (1) ◽  
pp. 110-116 ◽  
Author(s):  
David W. Pearce ◽  
John S. Taylor ◽  
J. Mason Robertson ◽  
K. Neil Harker ◽  
Edward J. Daly
Keyword(s):  
Acetic Acid ◽  
Abscisic Acid ◽  
Apical Dominance ◽  
Axillary Buds ◽  
Elytrigia Repens ◽  
Indole 3 Acetic Acid

Growth of axillary buds of Brussels sprouts (Brassica oleracea var. bullata sub var. gemmifera)

1991 ◽  
Vol 117 (2) ◽  
pp. 207-212 ◽  
Author(s):  
S. J. Wilcockson ◽  
A. E. Abuzeid
Keyword(s):  
Dry Matter ◽  
Axillary Buds ◽  
Dry Matter Accumulation ◽  
Fresh Weight ◽  
Brussels Sprouts ◽  
Size Profile ◽  
Constant Rate ◽  
Bud Size ◽  
Bud Growth ◽  
Subtending Leaves

SUMMARYIn 1984 and 1985, the growth of axillary buds of Brussels sprouts plants was studied at Cockle Park, Northumberland, UK. Bud growth commenced in late September or early October and continued at all nodes until the final harvest in December. Total bud yield increased at a broadly constant rate until late November but at a decreasing rate thereafter. Plants produced c. 100 nodes with buds ≥ 5 mm diameter. The largest buds were c. 40 mm diameter and 25 g fresh weight. Bud size increased from the base of the stem upwards to between the 20th and 40th nodes and then decreased towards the apex. Nodes 20–40 (20% of the total) produced c. 40–45% of total bud yield. The size profile of leaves along the stem followed a similar pattern to the buds and the largest buds were in the axils of the largest leaves. There were close relationships between bud fresh weight and size, bud fresh weight and size, bud fresh weight and volume and log10 bud fresh weight and log10 bud size (r2 ≥ 0·995). The density of buds was c. 0·8 and bud fresh weight doubled for each 5 mm increase in bud diameter.Current photosynthesis of the leaf canopy was apparently the major source of assimilates for bud growth. A C14 tracing experiment suggested that growth of individual buds was mainly supported by their subtending leaves. There was no evidence of re-translocation of dry matter from dying leaves or the stems to buds or of substantial production of dry matter by the buds themselves. Rates of bud photosynthesis were only about 10% of the rate of leaves. The continued increase in bud fresh weight and size at the lowest nodes when leaves were senescing rapidly and after they had abscissed was probably mainly the result of water uptake rather than dry matter accumulation.

scholarly journals Brassinosteroid signaling integrates multiple pathways to release apical dominance in tomato

2021 ◽  
Vol 118 (11) ◽  
pp. e2004384118
Author(s):  
Xiaojian Xia ◽  
Han Dong ◽  
Yanling Yin ◽  
Xuewei Song ◽  
Xiaohua Gu ◽  
...  
Keyword(s):  
Regulatory Network ◽  
Apical Dominance ◽  
Plant Architecture ◽  
Response Regulator ◽  
Axillary Buds ◽  
Deficient Mutant ◽  
Type B ◽  
Apical Bud ◽  
Brassinosteroid Signaling ◽  
Bud Removal

The control of apical dominance involves auxin, strigolactones (SLs), cytokinins (CKs), and sugars, but the mechanistic controls of this regulatory network are not fully understood. Here, we show that brassinosteroid (BR) promotes bud outgrowth in tomato through the direct transcriptional regulation of BRANCHED1 (BRC1) by the BR signaling component BRASSINAZOLE-RESISTANT1 (BZR1). Attenuated responses to the removal of the apical bud, the inhibition of auxin, SLs or gibberellin synthesis, or treatment with CK and sucrose, were observed in bud outgrowth and the levels of BRC1 transcripts in the BR-deficient or bzr1 mutants. Furthermore, the accumulation of BR and the dephosphorylated form of BZR1 were increased by apical bud removal, inhibition of auxin, and SLs synthesis or treatment with CK and sucrose. These responses were decreased in the DELLA-deficient mutant. In addition, CK accumulation was inhibited by auxin and SLs, and decreased in the DELLA-deficient mutant, but it was increased in response to sucrose treatment. CK promoted BR synthesis in axillary buds through the action of the type-B response regulator, RR10. Our results demonstrate that BR signaling integrates multiple pathways that control shoot branching. Local BR signaling in axillary buds is therefore a potential target for shaping plant architecture.

scholarly journals Germination and initial development of canola and radish submitted to castor leaves aqueous extracts

2016 ◽  
Vol 7 (1) ◽  
pp. 104
Author(s):  
Carlos Alberto Gonsiorkiewicz Rigon ◽  
Adriana Tourinho Salamoni ◽  
Luan Cutti ◽  
Adalin Cezar Morais de Aguiar
Keyword(s):  
Seed Germination ◽  
Castor Bean ◽  
Ricinus Communis ◽  
Initial Growth ◽  
Aqueous Extracts ◽  
Brassica Napus L ◽  
Initial Development ◽  
Allelopathic Potential ◽  
Ricinus Communis L ◽  
Radish Seed

This study aimed to evaluate the allelopathic activity of aqueous extracts of castor bean (Ricinus communis L.) leaves on germination and initial growth of canola (Brassica napus L.) and radish (Raphanus sativus L.) seedlings. Two experiments were conducted, usingcanola seeds for the first, which was installed in a 2x7 factorial scheme (with two photoperiods – dark and light and seven extracts concentrations - 0, 1, 2, 4, 8, 16 and 32%). The second experiment consisted of an evaluation of radish seed germination submitted to seven concentrations of the extracts in the dark photoperiod. The germination of the canola seeds was reduced in the dark, and the use of extracts at concentrations of 16% and 32%inhibited seeds germination for both studied photoperiods. The radish seed germination was completely inhibited when the concentration of 32% was used, however, at the concentrations of 4, 8 and 16% a reduction on rootand hypocoyl development of the seedlings were observed, affirming the high allelopathic potential of castor bean aqueous extracts on canola and radish.

scholarly journals Phytochemical Screening and Antibacterial Evaluation of Conventional Antibiotics, Garlic and Ginger on Isolates from Fish Pond Water Samples in Awka, Anambra State, Nigeria

2021 ◽  
pp. 118-132
Author(s):  
O. R. Umeh ◽  
E. I. Chukwura ◽  
E. L. Okoye ◽  
E. M. Ibo ◽  
P. I. Egwuatu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Klebsiella Pneumoniae ◽  
Water Samples ◽  
Vibrio Parahaemolyticus ◽  
Pond Water ◽  
Inhibitory Effect ◽  
Hot Water ◽  
Aqueous Extracts ◽  
Phytochemical Screening ◽  
Conventional Antibiotics

Medicinal plants are used by almost 80% of the world’s population for their basic health care because of their low cost and ease in availability. In the last few decades, many bacteria have continued to show increasing resistance against current antibiotics. Aim: In this study, phytochemical screening and antibacterial effects of conventional antibiotics, garlic and ginger on test isolates from fish pond water samples were evaluated between May-November, 2019. Methods: Standard methods for phytochemical screening and antibacterial analysis were employed. Results: The results showed that amongst the antibiotics used for susceptibility test, Amoxicilin (30 µg) was mostly resisted by all the bacterial isolates except Staphylococcus aureus, Vibrio cholerae, Vibrio parahaemolyticus and Salmonella typhi while erythromycin (10 µg) was unable to inhibit Bacillus subtilis. Ciprofloxacin (10 µg) and pefloxacin (10 µg) inhibited the growth of all the isolates except Pseudomonas aeruginosa. The test isolates showed variable susceptibility to the garlic and ginger extracts (ethanol, methanol and hot water). The extracts inhibited the isolates in descending order; ginger ethanol > ginger methanol > garlic methanol > ginger hot water > garlic ethanol > garlic hot water. Vibrio parahaemolyticus, Vibrio cholerae and Staphylococcus aureus showed little resistant to the extracts while these extracts showed better activity on Klebsiella pneumoniae and Proteus mirabilis. Synergistic effect of garlic and ginger (500mg/ml) inhibited the growth of all the isolates with ethanol extracts having the highest zone diameter (29 mm) on Klebsiella pneumoniae and Proteus mirabilis while hot water extracts had the least zone of inhibition (18 mm) on Acinetobacter calcoaceticus and Vibrio parahaemolyticus. The minimum inhibitory and bactericidal concentration for ethanol, methanol and hot water extracts ranged from 31.25mg/ml to 62.5mg/ml and 62.5mg/ml to 125mg/ml respectively. Conclusion: The outcomes of susceptibility experiment depicted that ethanol and methanol extracts of garlic and ginger (each alone and in combination) showed more inhibitory effect than aqueous extracts and also the combination of ethanol, methanol and aqueous extracts resulted in inhibitory effect greater than each of the extracts when used singly. The use of ginger and garlic for control of fish pathogens appears to be justified.

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