The growth potential generated in citrus fruit under water stress and its relevant mechanisms

The phytohormone abscisic acid (ABA) is a major regulator of fruit response to water stress, and may influence cuticle properties and wax layer composition during fruit ripening. This study investigates the effects of ABA on epicuticular wax metabolism regulation in a citrus fruit cultivar with low ABA levels, called Pinalate (Citrus sinensis L. Osbeck), and how this relationship is influenced by water stress after detachment. Harvested ABA-treated fruit were exposed to water stress by storing them at low (30–35%) relative humidity. The total epicuticular wax load rose after fruit detachment, which ABA application decreased earlier and more markedly during fruit-dehydrating storage. ABA treatment changed the abundance of the separated wax fractions and the contents of most individual components, which reveals dependence on the exposure to postharvest water stress and different trends depending on storage duration. A correlation analysis supported these responses, which mostly fitted the expression patterns of the key genes involved in wax biosynthesis and transport. A cluster analysis indicated that storage duration is an important factor for the exogenous ABA influence and the postharvest environment on epicuticular wax composition, cuticle properties and fruit physiology. Dynamic ABA-mediated reconfiguration of wax metabolism is influenced by fruit exposure to water stress conditions.

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Differential Transcriptomic Regulation in Sweet Orange Fruit (Citrus sinensis L. Osbeck) Following Dehydration and Rehydration Conditions Leading to Peel Damage

Frontiers in Plant Science ◽

10.3389/fpls.2021.732821 ◽

2021 ◽

Vol 12 ◽

Author(s):

Paco Romero ◽

Maria Teresa Lafuente ◽

Fernando Alferez

Keyword(s):

Water Stress ◽

Citrus Sinensis ◽

Expression Profiles ◽

Citrus Fruit ◽

Crop Productivity ◽

Fruit Peel ◽

Cell Wall Modification ◽

Post Harvest ◽

Study Results ◽

Custom Made

Water stress is the most important environmental agent that contributes to the crop productivity and quality losses globally. In citrus, water stress is the main driver of the fruit peel disorders that impact the quality and market ability. An increasingly present post-harvest peel disorder is non-chilling peel pitting (NCPP). Non-chilling peel pitting is manifested as collapsed areas of flavedo randomly scattered on the fruit and its incidence increases due to abrupt increases in the environmental relative humidity (RH) during post-harvest fruit manipulation. In this study, we have used a custom-made cDNA microarray containing 44k unigenes from Citrus sinensis (L. Osbeck), covering for the first time the whole genome from this species, to study transcriptomic responses of mature citrus fruit to water stress. In the study, the global gene expression profiles of flavedo from Navelate oranges subjected to severe water stress are compared with those fruits subjected to rehydration stress provoked by changes in the RH during post-harvest, which enhances the development of NCPP. The study results show that NCPP is a complex physiological process that shares molecular responses with those from prolonged dehydration in fruit, but the damage associated with NCPP may be explained by unique features of rehydration stress at the molecular level, such as membrane disorganization, cell wall modification, and proteolysis.

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Developing mathematical model for diurnal dynamics of photosynthesis in Saccharum officinarum responsive to different irrigation and silicon application

PeerJ ◽

10.7717/peerj.10154 ◽

2020 ◽

Vol 8 ◽

pp. e10154

Author(s):

Krishan K. Verma ◽

Kai-Chao Wu ◽

Chhedi Lal Verma ◽

Dong-Mei Li ◽

Mukesh Kumar Malviya ◽

...

Keyword(s):

Water Stress ◽

Drought Stress ◽

Biomass Accumulation ◽

Saccharum Officinarum ◽

Stress Conditions ◽

Growth Potential ◽

Plant Performance ◽

Water Stress Condition ◽

Soil Irrigation ◽

Photosynthetic Responses

In the dynamic era of climate change, agricultural farming systems are facing various unprecedented problems worldwide. Drought stress is one of the serious abiotic stresses that hinder the growth potential and crop productivity. Silicon (Si) can improve crop yield by enhancing the efficiency of inputs and reducing relevant losses. As a quasi-essential element and the 2nd most abundant element in the Earth’s crust, Si is utilized by plants and applied exogenously to combat drought stress and improve plant performance by increasing physiological, cellular and molecular responses. However, the physiological mechanisms that respond to water stress are still not well defined in Saccharum officinarum plants. To the best of our knowledge, the dynamics of photosynthesis responsive to different exogenous Si levels in Saccharum officinarum has not been reported to date. The current experiment was carried out to assess the protective role of Si in plant growth and photosynthetic responses in Saccharum officinarum under water stress conditions. Saccharum officinarum cv. ‘GT 42’ plants were subjected to drought stress conditions (80–75%, 55–50% and 35–30% of soil moisture) after ten weeks of normal growth, followed by the soil irrigation of Si (0, 100, 300 and 500 mg L−1) for 8 weeks. The results indicated that Si addition mitigated the inhibition in Saccharum officinarum growth and photosynthesis, and improved biomass accumulation during water stress. The photosynthetic responses (photosynthesis, transpiration and stomatal conductance) were found down-regulated under water stress, and it was significantly enhanced by Si application. No phytotoxic effects were monitored even at excess (500 mg L−1). Soil irrigation of 300 mg L−1 of Si was more effective as 100 and 500 mg L−1 under water stress condition. It is concluded that the stress in Saccharum officinarum plants applied with Si was alleviated by improving plant fitness, photosynthetic capacity and biomass accumulation as compared with the control. Thus, this study offers new information towards the assessment of growth, biomass accumulation and physiological changes related to water stress with Si application in plants.

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Effects of Reduced Fall and Winter Irrigation on Citrus Fruit Quality

HortScience ◽

10.21273/hortsci.39.4.886c ◽

2004 ◽

Vol 39 (4) ◽

pp. 886C-886

Author(s):

Larry R. Parsons* ◽

Ed Etxeberria

Keyword(s):

Water Stress ◽

Organic Acids ◽

Fruit Quality ◽

Irrigation Water ◽

Irrigation Treatment ◽

Citrus Fruit ◽

Quality Parameters ◽

Stem Water Potential ◽

Orange Fruit ◽

Stem Water

Earlier work has shown that moderate water deficits imposed on citrus trees can increase fruit Brix without adversely affecting yield. Increased water restrictions have been imposed on citrus growers as Florida's population continues to increase. The objectives of this study were to determine: 1) the effects of no irrigation in the fall and winter on orange fruit quality parameters in Florida; and 2) amount of potential irrigation water savings. Trees were irrigated identically in the spring and summer. A non-irrigation treatment was started on Hamlin and Valencia oranges in September and October, respectively, while controls continued to be irrigated following established irrigation practices. An additional non-irrigated treatment was started at the same time on the Valencias that consisted of a soil covering with a water barrier (Tyvek) to exclude rainfall. Stem water potential was monitored during the fall and winter to estimate differences in water stress among the treatments. Brix and organic acids increased in fruit from non-irrigated treatments when compared to fruit from irrigated trees. Results also demonstrate that reduced irrigation did not affect yield greatly. Amount of irrigation savings was determined for both cultivars that differ in maturity dates.

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Appraisal by Numerical and Statistical Techniques of the Interaction of Moisture Stress and Phosphorus in the Development of the Tropical Legume Macroptilium atropurpureum (Dc.) Urb

Australian Journal of Botany ◽

10.1071/bt9800621 ◽

1980 ◽

Vol 28 (6) ◽

pp. 621 ◽

Cited By ~ 1

Author(s):

CT Gates ◽

RL Sandland

Keyword(s):

Water Stress ◽

Dry Weight ◽

Moisture Stress ◽

Growth Potential ◽

Nodule Development ◽

Nitrogen And Phosphorus ◽

Active Growth ◽

Macroptilium Atropurpureum ◽

Four Levels ◽

Rates Of Growth

The interaction of two levels of soil moisture and four levels of phosphorus on the development of Macroptilium atropurpureurn was studied for 18 harvests at 2-day intervals beginning on day 29 after sowing. Variates studied were fresh weight. dry weight, nitrogen and phosphorus contents for the laminae. stem plus petioles, root and nodules. The responses to treatment of these variates were shown by preliminary analyses of variance to contain complex patterns of interaction. The important facets of these interactions were then appraised by an extension of the usual univariate methods and the overall pattern of the interaction was delineated by a classificatory analysis. On the basis of the 14 attributes studied, there were six groups of responses to treatment. The lowest of these groups corresponded to failure to grow at low levels of phosphorus. The next group represented the response of nodules to treatment. Subsequent groups represented higher growth potential following efficient functioning of the nodules. Effects on nodulation were thus primary to subsequent patterns of plant development. Water stress greatly impaired both plant and nodule development, particularly at the higher two levels of phosphorus, whereas active growth occurred in normally watered plants. At these two phosphorus levels the effect of water stress was on development rather than on chemical composition, there being large absolute but small relative effects on chemical data. The lower levels of phosphorus supply contrasted with the two higher levels in having much lower rates of growth and of water loss.

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Non-irrigation in Fall and Winter Improves Florida Citrus Fruit Quality

HortScience ◽

10.21273/hortsci.41.4.971a ◽

2006 ◽

Vol 41 (4) ◽

pp. 971A-971

Author(s):

Larry Parsons ◽

Ed Etxeberria

Keyword(s):

Water Stress ◽

Fruit Quality ◽

Irrigation Water ◽

Citrus Fruit ◽

Negative Consequences ◽

Late Variety ◽

Florida Citrus ◽

Citrus Trees

Moderate water stress applied to citrus trees can increase fruit °Brix. Florida citrus growers have been required to use less irrigation as competition for water increases. The goal of this study was to see if irrigation could be eliminated in the fall and winter with few negative consequences. Water stress was imposed over a 3-year period on `Hamlin' and `Valencia' oranges (an early and late variety, respectively) by stopping irrigation in late October and restarting it in March. `Hamlin' fruit was harvested after 2 months of stress and `Valencia' fruit was harvested after 4 to 5 months of stress. In most years, °Brix was increased by water stress. Over a 3-year period, `Hamlin' yield was not affected by the water stress, but `Valencia' yield decreased slightly in the 3rd year. The increase in °Brix is beneficial economically, and, over 3 cm of irrigation water per year can be saved.

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