scholarly journals Physiology of Olive Leaf Abscission Induced by Phosphorus

1994 ◽  
Vol 119 (5) ◽  
pp. 956-963 ◽  
Author(s):  
Hisashi Yamada ◽  
George C. Martin
Keyword(s):  
Ambient Air ◽  
Abscission Zone ◽  
Leaf Abscission ◽  
Aminooxyacetic Acid ◽  
Ethylene Inhibitors ◽  
Olive Leaf ◽  
Ethylene Evolution ◽  
Exogenous Ethylene

Adding Al2O3 to 8-hydroxyquinoline citrate (8-HQC) solution did not alter the sensitivity of the leaf abscission zone to external ethylene. Exogenous ethylene at 791 nl·liter-1 for 72 to 120 hours and at 193 nl·liter-1 for 120 hours induced leaf abscission, whereas no leaf abscission occurred at 47 nl·liter-1 for 72 to 120 hours. Ethylene at 791 nl·liter-1 for 72 to 120 hours increased ethylene evolution, but the amount of ethylene evolved from the explants does not seem to be enough to induce leaf abscission. Three different ethylene inhibitors—aminooxyacetic acid (AOA), CoCl2, and aminoethoxyvinylglycine (AVG)—were used to determine whether P-induced leaf abscission was mediated through elevated ethylene evolution. Although AOA and CoCl2 failed to inhibit ethylene evolution from the explants stem-fed with NaH2PO4, AVG inhibited ethylene evolution. Each inhibitor, except 5 mm CoCl2, promoted leaf abscission when administered alone or with P. Our results reveal that P-induced olive leaf abscission may occur without elevated ethylene evolution. At 40 or 75 mm NaH2PO4, abscission did not occur until explants were removed from N2 and placed in ambient air.

scholarly journals 754 PB 146 Physiology of Olive Leaf Abscission Induced by Phosphorus

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 541b-541
Author(s):  
Hisashi Yamada ◽  
George C. Martin
Keyword(s):  
Abscission Zone ◽  
Leaf Abscission ◽  
Aminooxyacetic Acid ◽  
Ethylene Inhibitors ◽  
Olive Leaf ◽  
Ethylene Evolution ◽  
Ethylene Treatment ◽  
Exogenous Ethylene

The addition of Al2O3 to 8-hydroxyquinoline citrate (8-HQC) solution did not alter the sensitivity of the leaf abscission zone to external ethylene treatment. Exogenous ethylene at 791 nl·l-1 for 72 to 120h and at 193 nl·l-1 for 120h induced leaf abscission whereas at 47 nl·l-1 for 72 to 120h no leaf abscission occurred. Ethylene treatment at 791 nl·l-1 for 72 to 120h increased ethylene evolution, but the amount of ethylene evolved from the explants does not seem to be enough for leaf abscission induction. Three different ethylene inhibitors, aminooxyacetic acid (AOA), CoCl2 and am inoethoxyvinylglycine (AVG), were used to determine whether phosphorus-induced leaf abscission was mediated through elevated ethylene evolution. Although AOA and CoCl2 failed to inhibit ethylene evolution from the explants stem-fed with NaH2P O4, AVG inhibited ethylene evolution. Each of the inhibitors except for 5 mM CoCl2 promoted leaf abscission when administered alone or with phosphorus. Our results reveal that phosphorus induced olive leaf abscission occurs without elevated ethylene evolution, but that oxygen is required.

scholarly journals Phosphorus Effects on Olive Leaf Abscission

1994 ◽  
Vol 119 (4) ◽  
pp. 765-769 ◽  
Author(s):  
Tjasa Burnik-Tiefengraber ◽  
Kitren G. Weis ◽  
Barbara D. Webster ◽  
George C. Martin ◽  
Hisashi Yamada
Keyword(s):  
Abscission Zone ◽  
Leaf Abscission ◽  
Aminooxyacetic Acid ◽  
Potential Contribution ◽  
Ethylene Synthesis ◽  
Olive Leaf ◽  
Fresh Weight ◽  
Ethylene Evolution ◽  
Synthesis Inhibitor ◽  
Rule Out

When continuously stem-fed with 75 mm NaH2PO4, `Manzanillo' olive explants showed significant leaf abscission after 48 hours; by that time 1.042 mg·g-1 fresh weight P had accumulated in the abscission zone (AZ). The potential contribution of ethylene to phosphate-enhanced abscission was investigated using aminooxyacetic acid (AOA), an ethylene-synthesis inhibitor, and by measuring ethylene evolution in phosphate-treated explants. In combination with NaH2PO4, AOA did not affect leaf abscission. Though ethylene evolution from explants increased as leaf abscission was initiated, it was about two orders of magnitude less than the concentration necessary to induce leaf abscission as judged by exogenous treatments. Based on leaf-abscission kinetics, we have concluded that the mechanism of P-induced abscission is independent of gross measurement of evolved ethylene, but we cannot rule out ethylene confined to the AZ itself. When evaluated for P-induced leaf abscission, leaves of `Manzanillo' and `Sevillano' abscised earlier than `Ascolano' and `Mission'.

scholarly journals PHOSPHORUS EFFECTS ON OLIVE LEAF ABSCISSION

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 669f-669
Author(s):  
Tjasa B. Tiefengraber ◽  
Kitren G. Weis ◽  
George C. Martin ◽  
Barbara D. Webster
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Leaf Explants ◽  
Leaf Abscission ◽  
Ethylene Synthesis ◽  
Olive Leaf ◽  
Ethylene Evolution ◽  
Synthesis Inhibitor ◽  
Fruit Removal ◽  
Flower Production

Ethephon reduces olive fruit removal force but also results in leaf loss when used as a harvest fruit loosening agent and in reduction of flower production in the subsequent year. Phosphorus (P) has been implicated in the fruit loosening process. Nuclear magnetic resonance analyses indicate that P accumulates rapidly in olive leaf explant abscission zones. P also causes ethylene evolution prior to abscission; this effect appears to be direct. In combination with AOA an ethylene synthesis inhibitor, P accelerates `Manzanillo' leaf explants abscission, inducing significant abscission 3 days after treatment. These results will assist in development of a P use strategy that leads to fruit but not leaf abscission.

scholarly journals Ethephon induced oxidative stress in the olive leaf abscission zone enables development of a selective abscission compound

2017 ◽  
Vol 17 (1) ◽  
Author(s):  
S. Goldental-Cohen ◽  
C. Burstein ◽  
I. Biton ◽  
S. Ben Sasson ◽  
A. Sadeh ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Abscission Zone ◽  
Leaf Abscission ◽  
Olive Leaf

Localized cell growth in ethephon-treated olive leaf abscission zone

1981 ◽  
Vol 15 (4) ◽  
pp. 341-347 ◽  
Author(s):  
Vito S. Polito ◽  
Valerie Stallman
Keyword(s):  
Cell Growth ◽  
Abscission Zone ◽  
Leaf Abscission ◽  
Olive Leaf

Chlorsulfuron Induction of Leaf Abscission in Velvetleaf (Abutilon theophrasti)

Weed Science ◽  
1984 ◽  
Vol 32 (1) ◽  
pp. 132-137 ◽  
Author(s):  
Larry H. Hageman ◽  
Richard Behrens
Keyword(s):  
Ethylene Production ◽  
Cellulase Activity ◽  
Abutilon Theophrasti ◽  
Abscission Zone ◽  
Leaf Abscission ◽  
Butenoic Acid ◽  
Endogenous Ethylene

In velvetleaf (Abutilon theophrastiMedic. ♯3ABUTH), accelerated leaf abscission was a conspicuous response following foliar chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] carbonyl] benzenesulfonamide} treatment at 35 g ai/ha. Leaf abscission of treated plants was decreased by AVG [L-2-amino-4-(2-aminoethoxy)-trans-3-butenoic acid], an inhibitor of endogenous ethylene production. Chlorsulfuron stimulated ethylene production in the abscission zone and leaves of treated plants and also increased cellulase activity in the abscission zone. Accelerated leaf abscission of velvetleaf following chlorsulfuron application appears to result from chlorsulfuron-induced increases in endogenous ethylene production and cellulase activity.

Characters and origin of vessels with heterogenous structure in leaf and flower abscission zones

1999 ◽  
Vol 77 (2) ◽  
pp. 253-261 ◽  
Author(s):  
JP André ◽  
A M Catesson ◽  
M Liberman
Keyword(s):  
Cell Differentiation ◽  
Lycopersicon Esculentum ◽  
Secondary Xylem ◽  
Abscission Zone ◽  
Leaf Abscission ◽  
Cell Maturation ◽  
Casting Method ◽  
Plant Organs ◽  
Flower Abscission

The lifetime of many plant organs does not exceed a few weeks or a few months. These organs separate from the plant at the level of specialized abscission zones. The observation of xylem vasculature in abscission zones, a largely neglected subject, revealed original features when a vessel casting method was used. In all species of dicotyledons examined so far, flower and leaf abscission zones possessed heterogenous metaxylem vessels adjoining protoxylem and secondary xylem vessels with homogenous patterns of lignified thickenings. Heterogenous metaxylem vessel thickenings were helical, reticulate, or scalariform elements when in the abscission zone and pitted elements on the proximal and the distal sides. The origin and possible role of these vessels are considered. Data obtained on the flower abscission zone of tomato (Lycopersicon esculentum Mill.) suggest that formation of heterogenous vessels results from localized changes in the rhythm of cell differentiation and cell maturation inside the procambium-cambium continuum.Key words: abscission zone, cambium, differentiation, heterogenous vessels, procambium, vessel cast.

scholarly journals A Positive Role for Rhizobitoxine in Rhizobium-legume Symbiosis

1999 ◽  
Vol 12 (12) ◽  
pp. 1082-1089 ◽  
Author(s):  
Samuel Duodu ◽  
T. V. Bhuvaneswari ◽  
Thomas J. W. Stokkermans ◽  
N. Kent Peters
Keyword(s):  
Ethylene Biosynthesis ◽  
Nodule Development ◽  
Ethylene Inhibitors ◽  
Wild Type ◽  
Positive Role ◽  
Rate Limiting Step ◽  
Mutant Strains ◽  
Legume Symbiosis ◽  
Exogenous Ethylene ◽  
Rate Limiting

Although Bradyrhizobium elkanii is a mutualistic symbiont of legumes, it synthesizes a phytotoxin, rhizobitoxine, that causes chlorosis on a variety of legume hosts, giving a pathogenic character to these interactions. No positive role for rhizobitoxine has been previously demonstrated. Interestingly, rhizobitoxine inhibits the rate-limiting step for ethylene biosynthesis, a plant hormone known to inhibit or down-regulate nodule development. We hypothesized that rhizobitoxine plays a positive role in nodule development through its inhibition of ethylene biosynthesis. To test this hypothesis, host plants of B. elkanii were screened for a differential nodulation response to the wild-type and rhizobitoxine mutant strains. In Vigna radiata (mungbean), the rhizobitoxine mutant strains induced many aborted nodules arrested at all stages of pre-emergent and post-emergent development and formed significantly fewer mature nodules than the wild type. Experiments revealed that nodulation of mungbean plants is sensitive to exogenous ethylene, and that the ethylene inhibitors aminoethoxyvinylglycine and Co2+ were able to partially restore a wild-type nodulation pattern to the rhizobitoxine mutants. This is the first demonstration of a nodulation phenotype of the rhizobitoxine mutants and suggests that rhizobitoxine plays a positive and necessary role in Rhizobium-legume symbiosis through its inhibition of ethylene biosynthesis.

Sign in / Sign up

Export Citation Format

Share Document