Performance assessment of three old pear cultivars (Pyrus communis L.) to cope drought caused by climate change (original) (raw)
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Fruit Growing Research
Due to the soil and climate diversity of our country, fruit species meet favorable conditions for successful cultivation. In the context of actual climate changes, there is a need for integrated interdisciplinary research on the influence of microclimate changes, rapid diagnosis and real-time warning of changes caused by water insufficiency is strongly felt. The physiological responses of the trees to the water stress are dynamic, as the level of the water stress increases and the intensity of the response increases. The main factors on which depend the adaptation of the plants to the water stress are: the species, age, group of varieties, phenology, transpiration, photosynthetic and assimilation potential etc. The paper presents results obtained at the RIFG Pitesti-Maracineni during 2017-2019 period, regarding the influence of the water deficit registered in the last years, on some biological indicators of the trees (pollen viability, buds viability, cross trunk section surface) and quality of the fruits (fruit mass, firmness, soluble dry matter and total sugars content, acidity (pH), total sugars/pH ratio, vitamin C, in the fruits of some varieties, belonging to cherry, plum, peach and apple species, cultivated under superintensive system and with prospects for national extension into commercial farms.
Drought management strategies in fruit crops: An overview
Journal of Pharmacognosy and Phytochemistry, 2017
Environmental stresses play crucial role in the productivity, survival and reproductive biology of fruit plants as well as crops. Biotic and abiotic stresses, including drought, extreme temperature, scarcity of water, reducing quality of irrigation water and salinity in soil and water are problems which are becoming really acute. Due to their rapid and unpredictable effects, it is becoming very difficult for horticultural scientists and farmers to respond to challenges posed by biotic and biotic stresses. Among these stresses drought stress is considered to be a major threat to sustaining food security under current and more so in future climates. Keeping in mind challenges of drought and quality fruit production in stress prone areas, the present need before researchers and growers is to fight with the challenges posed by drought. There are many approaches like mulching, drip irrigation. Water conservation, use of growth retardants, proper nutrient management, use of antitranspiran...
Ecophysiological aspects of fruit crops in the era of climate change. A review
RESUMEN The increased concentration of carbon dioxide (CO2) and other greenhouse effect gases has led to global warming, which has resulted in climate change, increased levels of ultraviolet (UV) radiation and changes in the hydrological cycle, affecting the growth, development, production and quality of fruit crops, which undoubtedly will be difficult to predict and generalize because the physiological processes of plants are multidimen-sional. This review outlines how the effects of high/low solar radiation, temperature, water stress from droughts, flooding and rising levels of CO2 in the atmosphere affect fruit crops and their growth and physiology.
Fruits, 2005
Abstract --Introduction. Vegetative and fruit growth in fruit trees are differentially sensitive to water deficit during the season depending on the stage of fruit growth. Attempts have been made to evaluate the possibilities of using regulated deficit irrigation to control vegetative growth and save water in the fruit industry. Materials and methods. Effects of water stress (WS) and crop load (CL) on fruit growth and carbon assimilation rates were evaluated in a 7-year-old 'Elegant Lady' peach orchard. A completely randomized block design with 2 × 3 factors [irrigation with two levels (control and WS) and CL with three levels (light, commercial and heavy)] was used. Results and discussion. Both WS and CL affected fruit growth during the last stages but not early on. CL did not affect trunk water potential which was, however, significantly reduced by WS throughout the day and the season. Trunk water potential of water-stressed trees was lower than that of control trees throughout the day and the season regardless of CL. The magnitude of WS increased as the season progressed. Stomatal conductance, transpiration rate and CO 2 assimilation rate were not affected by CL but were reduced by WS. The trees responded (acclimated) to stress by progressively reducing their transpiration rate as the severity of stress increased. For each irrigation regime, assimilation rates were similar for all three crop levels. This indicated the existence of alternate sinks for assimilates when CL was low, which compensate for the reduction of fruit sink activity resulting from fruit thinning. Conclusion. Water deficit reduced trunk water potential, stomatal conductance, transpiration and photosynthesis in 'Elegant Lady' peach trees. However, CL had a limited effect on these functions. There were good correlations between trunk water potential and either stomatal conductance or assimilation rate in water-stressed trees but not in control trees. This indicates a poor coordination between leaf functions in peach trees under optimal conditions. However, these relationships were stronger under WS conditions. Thus, water use efficiency appeared to increase under water deficit conditions.
Physiological response of two apple genotypes to different water regimes under semiarid conditions
The effect of five irrigation regimes (20%, 40%, 60%, 80%, and 100% of "Class A" pan evaporation rate) were studied under field conditions in the main fruit growth phase of two apples genotypes, 'Red Ace Golden Delicious' and 'Red Edna', grafted on MM106 rootstock. The crop was harvested on 15 September 2008 and fruit size and weight were determined. Biochemical (chlorophylls a and b, proline) and physiological [net photosynthesis (A), stomatal resistance (Rs), transpiration rate (E) and intercellular CO 2 concentration (Ci)] parameters already known as stress indicators in apple trees were measured in leaves of trees subjected to different irrigation regimes. Fruit number and yield per tree were determined in the field; fruit flesh firmness, total soluble solids (TSS), and titratable acidity were measured subsequently. Transpiration rate did not differ significantly among the treatments at all sampling dates for both cultivars.
Agronomía Colombiana, 2023
Incidents of flooding in tropical and subtropical fruit trees have increased as a result of climate change. Because of flooding, the anaerobic conditions of the rhizosphere increase the conditions for phytotoxicity and infection by pathogenic fungi and bacteria. Due to oxygen depletion in waterlogged soils, growth, functions of the roots and of the entire plant are impaired. The decrease in the photosynthetic rate is considerable because of the reduced functional leaf area because of chlorosis, necrosis, leaf drop and stomatal closure, as well as chlorophyll degradation. Plants have developed different morphological, physiological, and biochemical adaptations to survive hypoxic stress. Some fruit trees form an aerenchyma in roots for the diffusion of oxygen from the aerial parts, create aerenchyma-containing adventitious roots, rapidly elongate stems into deeply flooded soils; or they form hypertrophied lenticels, like some mango varieties. Measures for better adaptations and tolerance of tropical fruit trees to climatic impact include the following: adaptations of the cultivated terrain, selection of varieties, rootstocks more tolerant to hypoxic stress, pruning to reestablish the balance of the aerial part/roots, and foliar applications (e.g., of glycine betaine or hydrogen peroxide (H2O2)). Mycorrhizal colonization of roots can increase tolerance to waterlogging, while the application of fertilizers, such as CaOor MgO, can improve the redox potential of flooded soils. We present results of studies on this problem for the following fruits: yellow passion fruit (Passiflora edulis f. flavicarpa) and purple passion fruit (P. edulis f. edulis), cape gooseberry (Physalis peruviana), lulo or naranjilla (Solanum quitoense), tree tomato (Solanum betaceum), citrus (Citrus spp.), guava (Psidium guajava), papaya (Carica papaya), and mango (Mangifera indica).
Scientia Horticulturae, 2017
In order to screen pomegranate cultivars for drought tolerance, few rapid, less expensive and reliable methods were used. Two-year-old pomegranate (Punica granatum L.) plants of various commercial cultivars namely Rabab-e-Neyriz' ('Rabab'), 'Shishe-cape -Ferdows' ('Shishecap'), 'Malas-e-Saveh' (M-Saveh), 'Malas-e-Yazdi' ('M-Yazdi'), and 'Ghojagh-e-Qom' ('Ghojagh') were grown in large containers filled with a mixture of leaf mould, sand, and soil (1:1:1, by volume) in greenhouse. The plants were subjected to 14-day drought stress by withholding irrigation, followed by re-watering for 7 days. Midday stem water potential (stem), leaf relative water content (RWC), membrane stability index (MSI), leaf dry mass per area (LMA), rapid test for drought tolerance (DTI), gas exchange parameters including net photosynthesis (A n), leaf scale transpiration (T r), and stomatal conductance (g s), and intrinsic water use efficiency (IWUE) were determined in well-watered and drought-stressed plants. All cultivars showed an ability to tolerate drought stress, but 'Ghojagh' exhibited more tolerance, with a higher RWC and stem and a greater osmotic adjustment. 'Ghojagh' also revealed higher cell membrane stability and IWUE and a lower reduction in net CO 2 assimilation rate. This study found that 'M-Yazdi' was more vulnerable to severe water stress, and displayed the lowest degree of cell membrane stability as compared to the other examined cultivars and showed no recovery for RWC at the end of recovery period.
Fruits, 2006
Abstract --Introduction. Fruit production is faced with water shortage, especially in areas with a Mediterranean climate characterized by a very long, dry and hot summer. Thus, the growers under such conditions must manage irrigation carefully by finding new strategies, including water stress management. Materials and methods. Effects of water stress (WS) and crop load (CL) on the carbon assimilation rate, fruit growth, crop yield and fruit quality (size and soluble solids content) were evaluated in a 7-year-old 'Elegant Lady' peach orchard (Winters, California, USA). The experimental design consisted of a completely randomized block factorial design with 2 × 3 factors: irrigation with two levels (control and WS trees) and crop load with three levels (light, commercial and heavy). Results and discussion. Both CL and WS affected fruit growth during the last stages but not early on. Crop load did not affect trunk water potential (TrWP) which, however, was significantly reduced by WS throughout the day and the season. The stomatal conductance (g s ), transpiration rate (E) and CO 2 assimilation rate (A) were not affected by CL, but they were reduced by WS. There were poor correlations between TrWP and either g s or A in control trees, indicating relatively poor coordination between leaf functions in peach trees under optimal conditions. Both WS and CL delayed the harvest date through their effect on ripening. Water stress significantly reduced the average crop fresh yield but hardly affected crop dry yield. Both WS and CL affected the distribution of fruit size categories, with the proportion of large fruit decreasing with the increase in crop load and the severity of WS. Conclusion. Water stress reduced fruit fresh weight and fruit fresh yield but not fruit dry weight or dry yield. Crop load reduced fruit fresh and dry weights and yields. Crop load had a negative effect on soluble solids content, while WS had a positive effect. Thus, CL reduced fruit size and soluble solids content, while WS reduced size but improved soluble solids concentration.
Water stress preconditioning to improve drought resistance in young apricot plants
Plant Science, 2000
The effect of water stress preconditioning was studied in one-year-old apricot plants (Prunus armeniaca L., cv. Búlida). Plants were submitted to different treatments: T-0 (control treatment) and T-1, drip irrigated daily; T-2 and T-3, irrigated daily at 50% and 25% of T-0, respectively; T-4 and T-5, irrigated to field capacity every 3 and 6 days, respectively. After 30 days, irrigation was withheld for 10 days, maintaining the T-0 treatment irrigated daily. After this period, the plants were re-irrigated to run-off and treated as control treatment. The stomatal closure and epinasty observed in response to water stress represented adaptive mechanisms to drought, allowing the plants to regulate water loss more effectively and prevent leaf heating. A substantial reduction in the irrigation water supplied combined with a high frequency of application (T-3 treatment) promoted plant hardening; the plants enduring drought better, due to their greater osmotic adjustment (0.77 MPa), which prevented severe plant dehydration and leaf abscission. Such a preconditioning treatment may be valuable for young apricot plants in the nursery stage in order to improve their subsequent resistance to drought. A 50% reduction in daily irrigation (T-2 treatment) did not significantly affect either gas exchange rates or leaf turgor, which suggests that water should be applied frequently if deficit irrigation is to be implemented.