scholarly journals Phosphorus-induced Leaf Abscission in Olive and Citrus Explants

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 541E-541
Author(s):  
Raphael Goren ◽  
Moshe Huberman ◽  
George C. Martin
Keyword(s):  
Citrus Sinensis ◽  
Ethylene Biosynthesis ◽  
Leaf Abscission ◽  
Olive Leaf ◽  
General Phenomenon ◽  
Olive Leaves ◽  
Biosynthesis Inhibitors ◽  
Ethylene Action ◽  
Inhibitory Period

Previous studies, in which the role of phosphorus in abscission of olive leaves was examined in the presence of ethylene biosynthesis inhibitors, have suggested that phosphorus induces abscission directly, without involvement of ethylene. In the present study, this possibility was further explored by comparing the effects of an ethylene biosynthesis inhibitor, aminoethoxyvinylglycine (AVG), and an ethylene action inhibitor, 2,5-norbornadiene (NBD), in olive [Olea europaea (L) cv. Manzanillo] and citrus [Citrus sinensis (L.) Osbeck cv. Shamouti]. In olive, leaf abscission was always induced in the presence of KH2PO4, with or without AVG and NBD (alone or in combination), but was more pronounced when KH2PO4 was applied alone. In citrus, the effect of KH2PO4 alone on the induction of leaf abscission and ethylene production was much stronger than that observed in olive. However, in the presence of NBD, KH2PO4 did not induce leaf abscission in citrus during the first 60 hr. Similar results were obtained when NBD was replaced by AVG, but, in this case, abscission was inhibited for only 48 hr. In both cases, ethylene was detected after the inhibitory period had ended. The results obtained with citrus indicate that the observed effect of KH2PO4 on the ethylene-independent induction of leaf abscission in olive is not a general phenomenon and may differ in different species.

scholarly journals Phosphorus-induced Leaf Abscission in Detached Shoots of Olive and Citrus

1998 ◽  
Vol 123 (4) ◽  
pp. 545-549 ◽  
Author(s):  
Raphael Goren ◽  
Moshe Huberman ◽  
George C. Martin
Keyword(s):  
Ethylene Production ◽  
Olea Europaea ◽  
Citrus Sinensis ◽  
Leaf Explants ◽  
Ethylene Biosynthesis ◽  
Leaf Abscission ◽  
Olive Leaf ◽  
Olive Leaves ◽  
Biosynthesis Inhibitor ◽  
Ethylene Action

Previous studies have demonstrated that phosphorus, which stimulates ethylene biosynthesis, induces abscission of olive leaves directly without the involvement of ethylene. In the present study this possibility was further explored by comparing the effects of an ethylene biosynthesis inhibitor, aminoethoxyvinylglycine (AVG), and an ethylene action inhibitor, 2,5-norbornadiene (NBD), in olive [Olea europaea (L.) `Manzanillo'] and citrus [Citrus sinensis (L.) Osbeck `Shamouti']. In olive, leaf abscission was always induced in the presence of KH2PO4 with or without AVG and NBD (alone or in combination), but it was much more pronounced when KH2PO4 was applied alone. In citrus, KH2PO4 did not induce leaf abscission in the presence of NBD during the first 48 (detached shoots) or 60 hours (leaf explants) despite the high levels of ethylene production by the tissues. Our results demonstrate that phosphorus can, at least partly, act independently of ethylene action in inducing leaf abscission in olive but not in citrus.

scholarly journals The Role of Phosphorus as an Abscission-inducing Agent for Olive Leaves and Fruit

1993 ◽  
Vol 118 (5) ◽  
pp. 599-604 ◽  
Author(s):  
Kiyoshi Banno ◽  
George C. Martin ◽  
Robert M. Carlson
Keyword(s):  
Morphological Difference ◽  
Leaf Abscission ◽  
Drying Rate ◽  
Olive Leaves ◽  
Leaf Petiole ◽  
Fruit Abscission ◽  
P Content ◽  
Effective Sensitivity ◽  
Citrate Phosphate

Citrate-phosphate buffer induced olive (Olea europaea L.) leaf abscission at pH 3, 5, or 7. Of several sources of P-induced leaf abscission, NaH2PO4 was the most effective. Sensitivity to P was shown by leaf abscission, leaf desiccation, or both among 32 species representing 22 genera. Applied P accumulates in petioles, but its effect on abscission does not seem to depend on ethylene production. The low P content in the ethephon molecule may have an additive effect in ethephon-induced abscission. Stem-fed NaH2PO4 or ethephon resulted in total leaf and fruit abscission. Of the chemicals applied as a foliar treatment, only NaH2PO4 caused fruit abscission with minimal leaf loss. Adding Al2O3 to adsorb P in treatment solutions delayed the abscission effect of ethephon and NaH2PO4. Adding glycerol to NaH2PO4 increased fruit abscission from 50% to ≈80% and leaf abscission from ≈9% to 18%. The presumed effect of glycerol is from slowing the drying rate and thereby increasing P penetration into the fruit abscission zone. The pedicel-fruit cavity is a collection basin for spray accumulation that is not present in the leaf petiole attachment to the stem. This morphological difference probably leads to greater absorption of abscission-inducing materials by fruit. Chemical name used: (2-chloroethyl)phosphonic acid (ethephon).

scholarly journals Root Initiation in Debladed Petioles from Juvenile and Mature English Ivy in Response to Inhibitors of Ethylene Biosynthesis and Action

1990 ◽  
Vol 115 (1) ◽  
pp. 128-131 ◽  
Author(s):  
Robert L. Geneve ◽  
Wesley P. Hackett ◽  
Bert T. Swanson
Keyword(s):  
Ethylene Biosynthesis ◽  
Aminooxyacetic Acid ◽  
Naphthalene Acetic Acid ◽  
Root Initiation ◽  
Hedera Helix ◽  
Mature Phase ◽  
Ethylene Action ◽  
Inhibitor Treatment ◽  
English Ivy

Several inhibitors of ethylene biosynthesis and action, as well as an atmospheric ethylene scrubber, were used to investigate the role of ethylene in adventitious root initiation in de-bladed petioles from the juvenile and mature phase of English ivy (Hedera helix L.). Induction of root primordia required NAA regardless of the inhibitor treatment. Difficult-to-root mature petioles have been shown to produce higher amounts of ethylene than easy-to-root juvenile petioles. However, mature petioles failed to root under any combination of NAA and inhibitor treatment, indicating that the continued evolution of ethylene in NAA-treated mature petioles was not responsible for the absence of a rooting response. Root initiation in juvenile petioles was not affected by treatment with the ethylene action inhibitors STS and NDE, nor by removal of atmospheric ethylene with KMnO. Inhibition of ethylene biosynthesis using AVG or AOA reduced root initiation in juvenile petioles, but this response was not well-correlated to the observed reduction in ethylene evolution. The inhibitory action of AVG could not be reversed by the addition of ethylene gas or ACC, which indicated that AVG could be acting through a mechanism other than the inhibition of ethylene biosynthesis. Chemical names used: 1-naphthalene acetic acid (NAA); l-aminocyclopropane-l-carboxylic acid (ACC); silver thiosulfate (STS); 2,5-norbornadiene (NDE); aminoethyoxyvinyl-glycine (AVG); aminooxyacetic acid (AOA).

scholarly journals 349 Studies on Postharvest Performance of Cut Racemes of Big Bend Bluebonnet

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 503D-503
Author(s):  
W.A. Mackay ◽  
D. Sankhla ◽  
T.D Davis ◽  
N. Sankhla
Keyword(s):  
Ethylene Biosynthesis ◽  
Flower Senescence ◽  
Delayed Senescence ◽  
West Texas ◽  
Big Bend ◽  
Highly Sensitive ◽  
Ethylene Action ◽  
And Performance ◽  
Flower Abscission

Racemes of Big Bend bluebonnet (Lupinus havardii Wats.), a winter annual native to far west Texas with attractive blue flowers, are currently being produced commercially as a specialty cut-flower crop. Our studies indicated that the key determinants of postharvest longevity and performance are flower abscission and flower senescence, both of which can be influenced by ethylene. Therefore, this study was undertaken to evaluate the role of some ethylene biosynthesis inhibitors (aminooxy acetic acid = AOA; cobalt = CO++; salicylic acid = SA) and an ethylene action inhibitor (silver thiosulfate = STS) on flower abscission and flower senescence of bluebonnet racemes. Depending on the concentration used (10 μM - 1 mM), AOA and CO++ exhibited variable effects on flower abscission, flower senescence and vaselife. SA (10-100 μM) slightly delayed senescence but did not affect abscission, while higher levels of SA (500 μM - 2 mM) slightly promoted abscission and also significantly enhanced the senescence of flowers on cut racemes. The effects of SA were found to be pH-dependent. However, STS nearly eliminated flower abscission and enhanced vaselife. The results also demonstrated that the abscission of bluebonnet flowers, in particular, is highly sensitive to ethylene.

Response of orchard 'Washington Navel' orange, Citrus sinensis (L.) Osbeck, to saline irrigation water. II. Flowering, fruit set and fruit growth

1989 ◽  
Vol 40 (2) ◽  
pp. 371 ◽  
Author(s):  
H Howie ◽  
J Lloyd
Keyword(s):  
Leaf Area ◽  
Citrus Sinensis ◽  
Fruit Set ◽  
High Salinity ◽  
Starch Content ◽  
Fruit Growth ◽  
Leaf Abscission ◽  
Navel Orange ◽  
Washington Navel ◽  
Floral Differentiation

Flowering, fruit set and fruit growth of 'Washington Navel' orange fruit was monitored on 24-year-old Citrus sinensis trees on Sweet orange rootstocks that had been irrigated with either 5 or 20 mol m-3 NaCl for 5 years preceding measurements.Trees irrigated with high salinity water had reduced flowering intensities and lower rates of fruit set. This resulted in final fruit numbers for trees irrigated with 20 mol m-3 being 38% those of trees irrigated with 5 mol m-3 NaCl. Final fruit numbers were quantitatively related to canopy leaf area for both salinity treatments.Despite little difference between trees in terms of leaf area/fruit number ratio, slower rates of fruit growth were initially observed on high salinity trees. This effect was not apparent during the latter stages of fruit development. Consequently, fruit on trees irrigated with 20 mol m-3 NaCl grew to the same size as fruit on trees irrigated with 5 mol m-3 NaCl, but achieved this size at a later date. Measurements of Brix/acid ratios showed that fruit on high salinity trees reached maturity standards 25 days after fruit on low salinity trees.Unimpaired growth of fruit on high salinity trees during summer and autumn occurred, despite appreciable leaf abscission, suggesting that reserve carbohydrate was utilized for growth during this period. Twigs on high salinity trees had much reduced starch content at the time of floral differentiation in winter. Twig starch content and extent of floral differentiation varied in a similar way when examined as a function of leaf abscission. This suggests that reduced flowering and fruit set in salinized citrus trees is due to low levels of reserve starch, most of which has been utilized to support fruit growth in the absence of carbohydrate production during summer and autumn.

scholarly journals Correlation between morphoagronomic traits and resistance to ethylene action in ornamental peppers.

2015 ◽  
Vol 33 (2) ◽  
pp. 151-154 ◽  
Author(s):  
Mayana F Nascimento ◽  
Elizanilda R Rêgo ◽  
Naysa FF Nascimento ◽  
Rusthon MC Santos ◽  
Claudio H Bruckner ◽  
...  
Keyword(s):  
Pearson Correlation ◽  
Production Quality ◽  
Matter Content ◽  
Leaf Abscission ◽  
Fluorescent Light ◽  
Dry Matter Content ◽  
Anther Length ◽  
Ethylene Action ◽  
Ripe Stage ◽  
Pericarp Thickness

The post-production quality of ornamental peppers can be shorted due to exposure to ethylene. The concentration of this phytohormone at 10 µL/L induces leaf, fruit and flowers abscission, ripening of climacteric fruits, organ senescence, seed germination and seedling growth. We evaluated the correlation between pepper morphoagronomic traits and resistance to ethylene on ornamental peppers. Two genotypes, one resistant (UFPB 132), a susceptible (UFPB 134), and two hybrids (DR x PN) were utilized (76 x PN) to assess the susceptibility or resistance to ethylene. The experimental design was completely randomized, with four replications. First, 19 morphoagronomic characteristics were analyzed when the plants had 30% of fruits at the ripe stage. At this stage, the pots were transferred to a room at 25oC with 8-10 µmol/s/m2 of white fluorescent light. Afterwards, the pots were placed in a 60-L container and treated with ethylene at final concentration of 10 µL/L. The plants were exposed to ethylene for 48 hours and then kept at room temperature for further analysis. Afterwards, the number of leaves and fruits was determined at time zero and after 144 hours after end of the ethylene treatment. The Pearson correlation was calculated for each pair of variables and submitted to t-test (p≤0.05). We observed high occurrence of a significant positive correlation (>0.95) between leaf abscission and the anther length, major fruit width, pedicel length, pericarp thickness and dry matter content of the fruits. No significant correlation between fruit abscission and morphological evaluated variables was found. These results show the possibility to use morphological measurements to select plants resistant to leaf abscission induced by ethylene, while for the abscission of fruits, No relation to the morphological parameters evaluated in this experiment was possible to be established.

scholarly journals Hesperidin and SARS-CoV-2: New Light on the Healthy Functions of Citrus Fruit

2020 ◽  
Author(s):  
Paolo Bellavite ◽  
Alberto Donzelli
Keyword(s):  
Immune System ◽  
Citrus Sinensis ◽  
Viral Infections ◽  
Citrus Fruit ◽  
Short Review ◽  
Citrus Fruits ◽  
Early Proteins ◽  
Main Protease ◽  
The Many

Among the many approaches to COVID-19 prevention, the possible role of diet has so far been somewhat marginal. Nutrition is very rich in substances with a potential beneficial effect on health and some of these could have an antiviral action or in any case be important in modulating the immune system and in defending cells from the oxidative stress associated with infection. This short review draws the attention on some components of Citrus fruits and especially of the orange (Citrus sinensis), well known for its vitamin content, but less for the function of its flavonoids. Among the latter, hesperidin has recently attracted the attention of researchers, because it binds to the key proteins of the SARS-CoV-2 virus. Several computational methods, independently applied by different researchers, showed that hesperidin has a low binding energy both with the coronavirus "spike" protein, and with the main protease that transforms the early proteins of the virus (pp1a and ppa1b) into the complex responsible for viral replication. The affinity of hesperidin for these proteins is comparable if not superior to that of common chemical antivirals. The preventive efficacy of vitamin C, at dosage attainable by diet, against viral infections is controversial, but recent reviews suggest that this substance may be useful in case of increased stress on the immune system. Finally, the reasons that suggest undertaking appropriate research on the Citrus fruits addition in the diet, as a complementary prevention and treatment of COVID-19, are discussed.

scholarly journals In vitro effects of fungicides on conidium germination of Spilocaea oleagina the cause of olive leaf spot

2005 ◽  
Vol 58 ◽  
pp. 278-282
Author(s):  
E.O. Obanor ◽  
M. Walter ◽  
E.E. Jones ◽  
M.V. Jaspers
Keyword(s):  
Leaf Spot ◽  
Copper Hydroxide ◽  
Olive Leaf ◽  
Olive Leaves ◽  
Benzimidazole Fungicides ◽  
Low Concentrations ◽  
Conidium Germination ◽  
In Vitro Effects ◽  
Demethylation Inhibitor

Twenty fungicides were tested in vitro for their effects on the germination of conidia of Spilocaea oleagina the fungus that causes olive leaf spot Conidia used in this evaluation were obtained from naturally infected olive leaves in Canterbury Of the fungicides tested kresoximmethyl and captan were the most effective in preventing conidium germination at low concentrations with EC50 values of 0002 and 0003 g/ml respectively The newer fungicides boscalid and boscalid/pyraclostrobin were also effective (EC500031 and 0006 g/ml respectively) Of the benzimidazole fungicides tested carbendazim was effective (EC500005 g/ml) but thiophanatemethyl was not (EC5026 g/ml) None of the demethylation inhibitor fungicides tested were very effective (EC50 values gt;1 g/ml) except flusilazol (EC500075 g/ml) Two coppercontaining fungicides copper hydroxide and copper sulphate were ineffective for preventing conidium germination (EC5030 and 443 g/ml respectively) This study has identified candidate fungicides for further evaluation as tools for management of olive leaf spot

scholarly journals Study the Effects of Olive Leaves Extracts in the activity of the enzyme GOT and their Biological Activities

2017 ◽  
Vol 14 (1) ◽  
pp. 48-59
Author(s):  
Baghdad Science Journal
Keyword(s):  
Aqueous Extract ◽  
Large Scale ◽  
Chemical Elements ◽  
Biological Activities ◽  
Olive Tree ◽  
Food Preservation ◽  
The Body ◽  
Aqueous Extracts ◽  
Olive Leaf ◽  
Olive Leaves

The olive tree, has been used it is important plant for the time being some of their parts on a large scale in the treatment of gastrointestinal disorders and stimulate circulation . Moreover, it is used as antibacterial material and also to address some of the respiratory system, diabetes, food preservation osteoporosis. This study involved the collection of olive leaves from different areas in Baghdad / Iraq. These leaves have been harvested, wash it, then dried and crushed, where the study aimed to identify the active ingredients and chemical elements in the olive leaf as well as its effect on the action of GOT enzyme .The study showed that the aqueous extracts (cold and hot) of the olive leaves powder are acidic in nature pH values are of (5.74 and 5.40) for the aqueous extracts hot and cold respectively. Study revealed the extract contain the a collection of Glycosides, tannins, phenolic compounds, resins, flavonoids, alkaloids, terpenes and compound Alaolurobin. The study also showed ability to activate the enzyme GOT in cold aqueous extract (8.36%). and the percentage (27.35%) of hot aqueous extract. That can be analyzed to the presence of higher concentrations of the active compounds in hot aqueous extract compared with cold aqueous extract especially tannins working to activate enzymes carrier in the cell membrane in the body. The study showed that the analysis of thin layer chromatography, liquid high-performance, ( TLC, HPLC) in extract compounds of phenols olive leaf using a mixture (chloroform, acetic acid) and a 2:5 was more impact in the Gram-positive Staphylococcus aureus, while less impact in a negative Gram Salmonella typhimurium. As proved accurate analysis of the chemical elements in powder of plant leaf olive tree and at different concentrations contain of chemical elements Major estimated by (g /kg) and trace estimated by (mg/kg). Since the existence of these elements led to increasing of enzymatic effectiveness through an increase process of activity the enzyme (GOT), which plays role of important in our bodies being gives indication of the nature of the work and effectiveness of the activity of some members of the body (liver, kidney, pancreas, etc.).

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