Postharvest floral organ fall in Geraldton waxflower (Chamelaucium uncinatum Schauer)

1993 ◽  
Vol 33 (4) ◽  
pp. 481 ◽  
Author(s):  
DC Joyce
Keyword(s):  
Water Deficit ◽  
Room Temperature ◽  
Floral Organ ◽  
Vase Life ◽  
Naphthaleneacetic Acid ◽  
Fungal Development ◽  
Compression Load ◽  
Severe Water Deficit ◽  
Flower Abscission ◽  
Chamelaucium Uncinatum

Possible reasons for, and prevention of, postharvest floral organ fall in Geraldton waxflower (Chamelaucium unciizatum Schauer) were studied. An 11-kg compression load, equivalent to the lidding of a carton, caused flower fall amounting to 1% of the fresh mass of 420-g bunches. Fungal development also resulted in flower abscission. Healthy flowers produced little ethylene (e.g. 0.05 �L/kg.h), while infected flowers produced much more (e.g. 7.71 �L/kg.h) and were shed. Treatment with fungicide (iprodione + mancozeb) and antiethylene compounds [e.g. silver thiosulfate (STS) pulse, Purafil sorbant] reduced flowerfall in packaged flowers. Cut sprigs which suffered severe water deficit also shed flowers. In cv. Elegance, drying to -3.61 MPa elevated ethylene production (e.g. 1.35 �L/kg . h). Flowerfall induced by water deficit could be reduced by pretreatment with a STS pulse (0.5 mmol Ag+/L for 15-22 h at 0�C or 4 mmol Ag+/L for 20-30 min at about 20�C). Pretreatment with a naphthaleneacetic acid dip (50 mg/L for 1 min at room temperature) shortened the vase life of Elegance.

Effects of postharvest methyl jasmonate treatments against Botrytis cinerea on Geraldton waxflower (Chamelaucium uncinatum)

2006 ◽  
Vol 46 (5) ◽  
pp. 717 ◽  
Author(s):  
J. X. Eyre ◽  
J. Faragher ◽  
D. C. Joyce ◽  
P. R. Franz
Keyword(s):  
Methyl Jasmonate ◽  
Botrytis Cinerea ◽  
Induced Systemic Resistance ◽  
Floral Organ ◽  
Ethylene Biosynthesis ◽  
Systemic Resistance ◽  
Meja Treatment ◽  
Flower Abscission ◽  
Chamelaucium Uncinatum

Cut Geraldton waxflower (Chamelaucium uncinatum Schauer) flowers are often infected with Botrytis cinerea. Release of infection from quiescence can cause ethylene production by invaded host tissues and result in flower abscission. Postharvest floral organ abscission is a major problem for the commercial waxflower industry. Methyl jasmonate (MeJA) occurs naturally in plant tissue and has a signalling role in eliciting induced systemic resistance against disease. MeJA treatments have been shown to suppress B. cinerea infecting cut rose flowers. The present experiments investigated the potential of exogenous MeJA treatments for B. cinerea management on harvested waxflower. MeJA treatments of 10 and 100 µL liquid MeJA/L of air applied to cv. Purple Pride and 1 µL MeJA/L to cv. Mullering Brook gave reductions in disease severity for uninoculated stems. However, concentrations of 100 µL MeJA/L applied to Purple Pride in addition to 1 and 10 µL MeJA/L applied to Mullering Brook increased the incidence of floral organ fall. Flower abscission upon treatment with MeJA may be due to induced systemic resistance-associated upregulation of ethylene biosynthesis. MeJA treatments had no direct effect on B. cinerea hyphal elongation in vitro. Collectively, these results show that while MeJA treatment may elicit defence in waxflower against Botrytis, the chemical also causes floral organ fall. Thus, exogenous MeJA treatments do not have potential for B. cinerea management on harvested waxflower.

Calcium treatment of harvested Geraldton waxflower does not enhance postharvest quality

2003 ◽  
Vol 43 (6) ◽  
pp. 655 ◽  
Author(s):  
M. N. Taylor ◽  
D. C. Joyce ◽  
A. H. Wearing ◽  
D. H. Simons
Keyword(s):  
Cell Walls ◽  
Postharvest Quality ◽  
Vase Life ◽  
Plant Cell Walls ◽  
Calcium Treatment ◽  
Postharvest Application ◽  
Tissue Calcium ◽  
Structural Barrier ◽  
Flower Abscission ◽  
Chamelaucium Uncinatum

Postharvest flower abscission from cut Geraldton waxflower (Chamelaucium uncinatum) is mostly caused by fungal invasion. Elevated plant tissue calcium concentrations through postharvest application reduces fungal disease severity in various crops. Such results may be explained by strengthening of plant cell walls by calcium. Strengthening provides a structural barrier to fungal hyphae, thereby restricting invasion of plant cells. Postharvest pulsing with calcium solution substantially increased calcium concentrations in waxflower tissues. 45Ca�tracer revealed calcium distribution throughout flowering sprigs, including infection sites such as stylar tissue. However, pulsing waxflower sprigs with calcium did not suppress either disease or flower abscission, nor did it enhance vase life.

Effect of postharvest dipping in insecticides on the vase life of Geraldton waxflower

1996 ◽  
Vol 36 (3) ◽  
pp. 373 ◽  
Author(s):  
KA Seaton ◽  
DC Joyce
Keyword(s):  
Wetting Agent ◽  
Vase Life ◽  
Ambient Temperatures ◽  
Application Rates ◽  
Wetting Agents ◽  
Chamelaucium Uncinatum

In postharvest dipping treatment of Geraldton waxflower (Chamelaucium uncinatum), 13 insecticides tested at recommended application rates caused no visual injury, but some reduced vase life. Flowers of cv. Purple Pride were more sensitive to insecticides than leaves. There was no loss of vase life of flowers following dipping in chlorpyrifos, dimethoate or permethrin. Following dipping in deltamethrin, carbaryl, dichlorvos, cypermethrin, endosulfan or fenvalerate there was 31-49% loss of vase life. No loss of vase life was observed for cv. Alba, after dipping in carbaryl, fenvalerate or dimethoate. Insecticide dips containing wetting agent and a fungicide (e.g. a combination of deltamenthrin, Aqua and benomyl) was a suitable dip for Geraldton waxflower. Wetting agents varied in their effect on vase life. Aqua shortened vase life less than Agral, and D-CTrate less than D-C-Tron. Stems rapidly lost weight when held out of water following dipping, and vase life was reduced when ambient temperatures were above 30�C or drying times exceeded 60 min. It was concluded that flowers should be kept cool and well hydrated following dipping treatment.

Defence mechanisms against production of free radicals in cells of ‘resurrection’ plants

1994 ◽  
Vol 102 ◽  
pp. 291-294
Author(s):  
Cristina L. M. Sgherri ◽  
Mike F. Quartacci ◽  
Adriana Bochicchio ◽  
Flavia Navari-Izzo
Keyword(s):  
Free Radicals ◽  
Water Deficit ◽  
Water Loss ◽  
Physiological Activity ◽  
Physiological State ◽  
Resurrection Plant ◽  
Resurrection Plants ◽  
Defence Mechanisms ◽  
Adaptation Mechanism ◽  
Severe Water Deficit

The ability of protoplasm to revive following severe water deficit is at its greatest in desiccation-tolerant or ‘resurrection’ plants. Boea hygroscopica is a resurrection plant that is able to survive air-dryness following slow dehydration (80% RH) in a physiological state called anabiosis (Schwab & Gaff 1990). However, this plant loses the ability to recover complete physiological activity following rapid water loss (0% RH).The ability to recover complete physiological activity following repeated protoplasmic dehydration of fully differentiated tissues is an adaptation mechanism unique to resurrection plants.

Anatomical adaptations of the desert species Stipa lagascae against drought stress

Biologia ◽  
2015 ◽  
Vol 70 (8) ◽  
Author(s):  
Façal Boughalleb ◽  
Raoudha Abdellaoui ◽  
Zied Hadded ◽  
Mohammed Neffati
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Deficit ◽  
Cortical Cell ◽  
Severe Drought ◽  
Leaf Rolling ◽  
Drought Period ◽  
Severe Water Deficit ◽  
Anatomical Adaptations ◽  
Stipa Lagascae

AbstractStipa lagascae R. & Sch. (perennial bunchgrass) is one of the most promising steppic species for arid and desert lands of Tunisia. The present study was designed to study the effect of drought on root and leaf anatomy, water relationship, and the growth of three- month-old S. lagascae plants, submitted to water deficit (5, 10, 15, 20, 30 days of withheld irrigation) and grown in pots in greenhouse conditions. The results show that water deficit treatments reduced the biomass accumulation (MS) and leaf water potential (Ψw) of plants. However, leaf relative water content (RWC) decreased significantly only at severe drought. The root’s anatomical features showed reduced root cross-sectional diameter under water deficit. Conversely, epidermis was unaffected by water stress. Moderate and/or severe water deficit (20-30 days) reduced significantly the cortex thickness, cortical cell size, stele diameter, xylem vessel diameter and the stele/root crosssectional ratio, while the number of cortical cells increased for severe water deficit. The cuticles and mesophyll of S. lagascae was thickened by moderate to severe drought and the entire lamina thickness was increased significantly by 5.8% only after 30 days of water deficit while epidermis was unaffected by water deficit. However, severe water deficit (30 days) decreased the width and the length of the bundle sheath. At the same time, the mesophyll cells size and both the xylem and phloem vessels diameter diminished by 12, 16.8 and 17.5%, respectively. Leaf rolling occurs as a response to water deficit and its level increases as the drought period is progressing in plants while reduced bulliform cells size occurred only at severe water deficit. Our findings suggest a complex network of root and leaf anatomical adaptations such as a reduced vessel size with lesser cortical and mesophyll parenchyma formation and increased leaf rolling. These proprieties are required for the maintenance of water potential and energy storage under water stress which can improve the resistance of S. lagascae to survive in extremely arid areas

Genotypic differences in leaf area maintenance contribute to differences in recovery from water stress in soybean

2008 ◽  
Vol 59 (12) ◽  
pp. 1075 ◽  
Author(s):  
R. J. Lawn ◽  
A. A. Likoswe
Keyword(s):  
Leaf Area ◽  
Water Deficit ◽  
Leaf Tissue ◽  
Water Deficit Stress ◽  
Dead Leaf ◽  
Genotypic Differences ◽  
Leaf Stage ◽  
Severe Water Deficit ◽  
Soybean Plants ◽  
Root Effects

Genotypic effects on leaf survival during water deficit stress and subsequent recovery were evaluated using soybean plants grown in tall cylinders in the glasshouse. An initial experiment sought to verify reported genotypic differences in leaf area maintenance under severe water deficit stress. A second experiment sought to test the hypothesis that these putative differences might affect recovery after stress was relieved. Two shoot genotypes, G2120 and cv. Valder, reported to have high and low leaf area retention, respectively, were used in both experiments. In order to preclude the possibility that the reported differences between G2120 and Valder were related to root rather than shoot traits, each shoot was grafted at the cotyledonary stage onto 2 non-self root genotypes, cv. Leichhardt and PI416937. Leichhardt has an apparently normal root, while PI416937 has been reported to be ‘extensively fibrous-rooted’. In the first experiment, water was withheld at the first trifoliolate leaf stage and the plants subjected to terminal water deficit stress. Consistent with the previous report, leaf area was maintained for longer into the stress by the G2120 shoots, with rapid loss of lower leaves not starting until c. 90% of plant-available water (PAW) had been depleted, compared with c. 80% for Valder. The Valder leaves also showed more ‘firing’ damage, with large patches of dead leaf tissue on the retained leaves. Also consistent with the previous report, leaf epidermal conductance to water vapour was lower in G2120 than in Valder. There were no apparent root effects. In the second experiment, water was again withheld at the first trifoliolate leaf stage, and treatments were re-watered when 80%, 85%, 90%, and 95% of the estimated PAW was extracted. Again, G2120 shoots showed better leaf area maintenance during the drying cycle, and less firing damage. When the plants were re-watered, the re-growth of G2120 generally exceeded that of Valder at all levels of PAW depletion. The differences in recovery between G2120 and Valder shoots were sufficient to have agronomic relevance, and confirmed the hypothesis that leaf area retention can affect recovery after severe water deficit stress. Root effects were relatively small. During the drying cycle, leaflet growth was marginally enhanced by Leichhardt relative to PI416937 roots. After re-watering, there was stronger recovery of plants with PI416937 roots, especially those with G2120 shoots. The basis of the differences between the root genotypes is not known but the stronger recovery of PI416937 may reflect its putative ‘extensively fibrous’ nature.

scholarly journals Influence of electrical conductivity on water uptake and vase life of cut gladiolus stems

2015 ◽  
Vol 21 (2) ◽  
pp. 221
Author(s):  
Lucas Cavalcante Da Costa ◽  
Fernanda Ferreira De Araújo ◽  
Teresa Drummond Correia Mendes ◽  
Fernando Luiz Finger
Keyword(s):  
Electrical Conductivity ◽  
Water Uptake ◽  
Room Temperature ◽  
Tap Water ◽  
Vase Life ◽  
Distilled Water ◽  
Cut Flowers ◽  
Water Ph ◽  
Maximum Water ◽  
Standard Composition

<p>Several experiments reveal that distilled water varies among different laboratories and also does not have a standard composition. Water electrical conductivity (EC) of vase solution is one of the parameters that influence the water uptake by cut flowers. Therefore, the objective of this work was to evaluate the influence of electrical conductivity on water uptake and vase life in cut stems of gladiolus. The stems harvested and kept in distilled water (pH 6.6, EC &lt;0.01dS m-1) and tap water (pH 7.0, EC 0.75 dS m-1) at room temperature. Flowers kept in tap water showed lower fresh weight loss after the second day and higher water uptake during vase life. In a second set of experiments, we verified the limit EC saturation supported by the flower. For this, flowers were placed in individual test tubes containing four different solutions with varying ion concentrations. Solution 2 (EC 0.60 dS m-1) promoted increased vase life and allowed maximum water uptake by the flowers. The results show that the electrical conductivity of vase solution is a major parameter in experiments with vase life of cut gladiolus. The presence of ions in the vase solution increases the overall vase life and improves water uptake of flowers with favorable optimal EC between 0.60 to 0.87 dS m-1.</p>

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