Sugars, hormones, and environment affect the dormancy status in underground adventitious buds of leafy spurge (Euphorbia esula)

Signals from both leaves and apical or axillary meristems of leafy spurge are known to inhibit root bud growth. To test the hypothesis that carbohydrates and growth regulators affect root bud growth, decapitated leafy spurge plants were hydroponically treated with glucose, sucrose, gibberellic acid (GA), abscisic acid (ABA), 1-naphthaleneacetic acid (NAA), 6-benzylaminopurine (BA), and a GA biosynthesis inhibitor, paclobutrazol. Both glucose and sucrose caused suppression of root bud growth at concentrations of 30 mM. The inhibitory effect of sucrose was counteracted by GA at 15 μM. In contrast, BA, ABA, NAA, and paclobutrazol inhibited root bud growth at concentrations as low as 1, 2, 1, and 16 μM, respectively. Sugar and starch levels were also determined in root buds at various times after decapitation. Buds of intact plants contained the highest level of sucrose compared with buds harvested 1, 3, and 5 d after decapitation. To determine how seasonal changes affect root bud dormancy, growth from root buds of field-grown plants was monitored for several years. Root buds of field-grown leafy spurge had the highest level of innate dormancy from October to November, which persisted until a prolonged period of freezing occurred in November or early December. Our data support the hypothesis that carbohydrates may be involved in regulating dormancy status in root buds of leafy spurge.

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Factors Affecting Translocation of 2,4-D in Leafy Spurge

Weed Science ◽

10.1017/s0043174500036791 ◽

1974 ◽

Vol 22 (2) ◽

pp. 167-171 ◽

Cited By ~ 3

Author(s):

James H. Hunter ◽

G. I. McIntyre

Keyword(s):

Acetic Acid ◽

Leafy Spurge ◽

Nitrogen Supply ◽

Euphorbia Esula ◽

Factors Affecting ◽

Bud Growth ◽

Dichlorophenoxy Acetic Acid ◽

Root Buds

The translocation of foliar-applied14C-labelled 2,4-D [(2,4-dichlorophenoxy)acetic acid] in seedlings of leafy spurge (Euphorbia esulaL.) was investigated. Approximately 90% of the tracer was extracted from the tissues with 80% ethanol. Seven days after treatment 48% of the14C in the shoot extract and 75% of that extracted from the root were identified chromatographically as 2,4-D. Translocation out of the treated leaves and into the shoot, root, and root buds was significantly increased both by decapitation of the shoot and by increasing the nitrogen supply. This effect is attributed to the marked promotion of bud growth produced by both of these treatments.

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The role of specific plant organs and polar auxin transport in correlative inhibition of leafy spurge (Euphorbia esula) root buds

Canadian Journal of Botany ◽

10.1139/b98-138 ◽

1998 ◽

Vol 76 (7) ◽

pp. 1227-1231 ◽

Cited By ~ 5

Author(s):

David P Horvath

Keyword(s):

Apical Dominance ◽

Auxin Transport ◽

Leafy Spurge ◽

Polar Auxin Transport ◽

Euphorbia Esula ◽

Transport Inhibitor ◽

Correlative Inhibition ◽

Auxin Transport Inhibitor ◽

Bud Growth ◽

Root Buds

Localization of the source of the signal(s) controlling correlative inhibition of leafy spurge root buds (underground adventitious shoot buds located on the lateral roots) was studied by sequential removal of various plant organs. It was determined that full correlative inhibition of root buds was lost only after excision of all aerial tissue from the plant, or after excision of all aerial tissue except the stem. If mature leaves or growing axillary buds (or both) were left intact, no growth of root buds was observed. The synthetic auxin, alpha-NAA, prevented release of apical dominance and subsequent outgrowth of stem and crown buds when applied to the cut end of the stem or crown. Exogenous application of NAA to either the stem or the crown had little effect on root bud growth. Application of the auxin transport inhibitor NPA around the base of the crown had no effect on root bud quiescence. These data are not consistent with the previous studies (Weed Sci. 35: 155-159 (1987)) that indicate a role for auxin in maintenance of correlative inhibition of root bud growth in leafy spurge. The results of auxin transport inhibitor studies presented here suggest that correlative inhibition of root bud growth does not rely on the classic polar auxin transport system.Nomenclature: leafy spurge, Euphorbia esula L. #3 EPHES; NAA, naphthalene acetic acid; NPA, N-1-naphthylphthalamic acid; TIBA, 2,3,5-triiodobenzoic acid.Key words: root buds, apical dominance, auxin, NPA.

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Transcriptome analysis of leafy spurge (Euphorbia esula) crown buds during shifts in well-defined phases of dormancy

Weed Science ◽

10.1614/ws-06-06r1.1 ◽

2006 ◽

Vol 54 (5) ◽

pp. 821-827 ◽

Cited By ~ 20

Author(s):

David P. Horvath ◽

James V. Anderson ◽

Mauricio Soto-Suárez ◽

Wun S. Chao

Keyword(s):

Gene Expression ◽

Gibberellic Acid ◽

Microarray Analysis ◽

Transcriptome Analysis ◽

Seasonal Changes ◽

Leafy Spurge ◽

Euphorbia Esula ◽

Ethylene Signaling ◽

Root Buds

Microarray analysis was used to follow changes in gene expression coinciding with seasonal changes in the dormancy status of crown buds of field-grown leafy spurge. Known cold-regulated genes were induced, and numerous gibberellic acid–responsive genes were down-regulated during the transition from paradormancy to endodormancy. Genes involved in photomorphogenesis were induced during endodormancy. Also, ethylene signaling responses were observed during ecodormancy rather than endodormancy. These results provide additional insights into the signals regulating expression of several genes previously associated with transition from paradormancy to growth in root buds.

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Correlative Inhibition and Dormancy in Root Buds of Leafy Spurge (Euphorbia esula)

Weed Science ◽

10.1017/s0043174500078966 ◽

1987 ◽

Vol 35 (2) ◽

pp. 155-159 ◽

Cited By ~ 13

Author(s):

Scott J. Nissen ◽

Michael E. Foley

Keyword(s):

Acetic Acid ◽

Late Summer ◽

Growing Season ◽

Leafy Spurge ◽

Euphorbia Esula ◽

Correlative Inhibition ◽

Napthaleneacetic Acid ◽

Bud Growth ◽

Indole 3 Acetic Acid ◽

Root Buds

Root buds of leafy spurge (Euphorbia esulaL. # EPHES) were found to be quiescent during most of the growing season due to correlative inhibition rather than innate dormancy. Excised root buds taken from plants that were fully flowering showed reduced elongation, indicating a period of innate dormancy. This innate dormancy could be eliminated by chilling plants for 8 days at 4 C. Root buds from plants showing late summer regrowth were no longer innately dormant. IAA (indole-3-acetic acid) and NAA (1-napthaleneacetic acid) completely inhibited the growth of excised leafy spurge root buds at concentrations of 10−3and 10−5M, respectively. A significant increase in root bud elongation was produced by 1 mM TIBA (2,3,5-triiodobenzoic acid) applied to stem and root tissue. These data provide further evidence for the involvement of IAA in correlative control of root bud growth in leafy spurge.

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Experimental Studies on Leafy Spurge (Euphorbia esula L.). III. Xylem Development in Relation to the Hypocotylary Bud Growth

Botanical Gazette ◽

10.1086/336929 ◽

1977 ◽

Vol 138 (3) ◽

pp. 305-311 ◽

Cited By ~ 3

Author(s):

M. V. S. Raju ◽

William N. Marchuk

Keyword(s):

Experimental Studies ◽

Leafy Spurge ◽

Euphorbia Esula ◽

Xylem Development ◽

Bud Growth

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Hormonal interaction in controlling apical dominance in soybeans

Canadian Journal of Botany ◽

10.1139/b71-243 ◽

1971 ◽

Vol 49 (9) ◽

pp. 1727-1731 ◽

Cited By ~ 16

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.

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Developmental studies on Euphorbia esula. Evidence of competition for water as a factor in the mechanism of root bud inhibition

Canadian Journal of Botany ◽

10.1139/b79-306 ◽

1979 ◽

Vol 57 (22) ◽

pp. 2572-2581 ◽

Cited By ~ 13

Author(s):

Gordon I. McIntyre

Keyword(s):

Water Content ◽

Leafy Spurge ◽

Euphorbia Esula ◽

Sand Culture ◽

High Humidity ◽

Developmental Studies ◽

Rate Of Emergence ◽

High Degree ◽

Considerable Support ◽

Root Buds

Seedlings of leafy spurge (Euphorbia esula L.) were grown in sand culture under controlled conditions and experiments were designed to test the hypothesis that competition for water between the root buds and the parent shoot is a significant factor in the mechanism of root bud inhibition. It was shown that the water content of the root buds increased by approximately 25% within 24 h of the removal of the parent shoot. Root bud length increased significantly between 24 and 48 h from shoot removal but while some of the buds continued to grow others were apparently reinhibited. Shoots with all immature tissue removed continued to exert a high degree of root bud inhibition but this inhibition was markedly reduced by keeping the plants in a high humidity. Increasing the humidity from approximately 50 to 95% also caused a significant increase in the rate of emergence and elongation of shoots produced from root buds following the removal of the parent shoot. This effect on emergence was suppressed by conditions presumed to reduce the degree of root bud aeration. Taken as a whole, the results lend considerable support to the concept of internal competition for water as a factor in the mechanism of root bud inhibition.

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Growth Regulators and Chemicals Stimulate Germination of Leafy Spurge (Euphorbia esula) Seeds

Weed Science ◽

10.1614/ws-07-179.1 ◽

2008 ◽

Vol 56 (4) ◽

pp. 516-522 ◽

Cited By ~ 19

Author(s):

Michael E. Foley ◽

Wun S. Chao

Keyword(s):

Growth Regulators ◽

Potassium Phosphate ◽

Fold Increase ◽

Leafy Spurge ◽

Euphorbia Esula ◽

Naphthaleneacetic Acid ◽

Citrate Buffer ◽

Baseline Information ◽

Alternating Temperature ◽

Effective Growth

Baseline information on inducing germination of dormant leafy spurge seeds with growth regulators and chemicals is lacking. This study was conducted to survey the effect of various substances on germination of leafy spurge seeds. The nontreated control seeds in this population were nearly fully imbibed in 3 h and displayed approximately 35% germination in 21 d under the normal alternating temperature of 20/30 C (16/8 h). Gibberellic acid (GA3, 10 mM) induced 65% germination at constant temperatures of 20 and 30 C. The alternating temperature increased the effectiveness of 10 mM GA3with 94% germination, a twofold increase over the control. Nontreated seeds did not germinate at the constant temperatures, suggesting that alternating temperature acts via a GA-independent pathway. Kinetin at 0.1 to 1 mM was no more effective than the control, but a saturated solution of kinetin induced 73% germination. Ethephon at 0.01 to 1 mM induced 58 to 66% germination, although there was little response to different concentrations. Ethylene gas at 1 ppm stimulated germination to 77%, a 1.8-fold increase over the control. Germination of seeds incubated continuously in 1 and 10 mM nitrate displayed 35 and 40% germination, respectively. Seeds pulsed for 24 h with 100 mM nitrate displayed 58% germination after 21 d. Potassium phosphate–citrate buffer (pH 3.4) and its individual components induced 60 to 70% germination. Fluridone (10 and 100 µM), 1-naphthaleneacetic acid (NAA, 0.1 to 10 mM), and ethanol (0.2 to 15%) had no effect on germination, but subsequent elongation in the presence of NAA was inhibited because of swelling of the radicle. This research reveals that GA3is the most effective growth regulator for germination of dormant leafy spurge seeds, and its effect is independent of temperature.

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AC 263,222 absorption and fate in leafy spurge (Euphorbia esula)

Weed Science ◽

10.1017/s0043174500091001 ◽

1998 ◽

Vol 46 (5) ◽

pp. 510-513 ◽

Cited By ~ 5

Author(s):

W. Mack Thompson ◽

Scott J. Nissen ◽

Robert A. Masters

Keyword(s):

Hplc Analysis ◽

Leafy Spurge ◽

Euphorbia Esula ◽

Total Recovery ◽

Plant Parts ◽

Crown Root ◽

Leaf Surfaces ◽

Below Ground ◽

Ac 263,222 ◽

Root Buds

Absorption, translocation, and metabolism of AC 263,222 by leafy spurge were studied over 8 d. Based on the amount of herbicide applied and recovered from the leaf surfaces, 40% of applied AC 263,222 was absorbed by leafy spurge 2 d after treatment (DAT), with no further absorption observed by 8 DAT. Eight DAT, 19% of applied [14C]-AC 263,222 had translocated to below-ground plant parts while 4% was exuded from the roots into the sand media. AC 263,222 was not metabolized 2 DAT in the crown, root, and root buds, but 42% was metabolized in the treated leaves. Only 17% of recovered [14C] was AC 263,222 in treated leaves 8 DAT (83% metabolized), while AC 263,222 accounted for 70% of recovered [14C] in the root and root buds. HPLC analysis indicated that the balance of [14C] was associated with a single, polar metabolite. Total recovery of [14C] was 88% at 8 DAT.

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