Leaf gas exchange and fruit yield in sweet orange trees as affected by citrus variegated chlorosis and environmental conditions

2009 ◽  
Vol 122 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Gustavo Habermann ◽  
João Domingos Rodrigues
Keyword(s):  
Gas Exchange ◽  
Environmental Conditions ◽  
Sweet Orange ◽  
Leaf Gas Exchange ◽  
Fruit Yield ◽  
Citrus Variegated Chlorosis ◽  
Orange Trees

scholarly journals Effects of Trunk-shaker Harvester and Ethephon on Plant Water Status, Leaf Gas Exchange, and Yield of Citrus Cultivated under Mediterranean Conditions

HortScience ◽  
2016 ◽  
Vol 51 (7) ◽  
pp. 861-872
Author(s):  
Rosana Moreno ◽  
Diego S. Intrigliolo ◽  
Carlos Ballester ◽  
Cruz Garcerá ◽  
Enrique Moltó ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Leaf Gas Exchange ◽  
Water Status ◽  
Fruit Yield ◽  
Plant Water Status ◽  
Plant Water ◽  
Current Season ◽  
Orange Trees ◽  
Time Of Harvest ◽  
Mediterranean Conditions

This work was aimed to study whether the application of ethephon as an abscission agent and mechanical harvest using a trunk shaker have any effect on plant water status, leaf gas exchange, and yield of mandarin and orange trees cultivated under Mediterranean conditions. The experiment was performed from 2008 to 2011 in five commercial orchards where parameters related to the plant water status and leaf gas exchange were measured before the application of ethephon, at harvest time and at different occasions after harvest. In addition, the effects of ethephon dose on yield in the current and subsequent seasons were also evaluated. Results showed that ethephon applications and mechanical harvest did not detrimentally affect plant water status in any of the cultivars studied. Furthermore, either had no effect or had a short temporal decrease effect on leaf gas exchange depending on the cultivar studied although with no consequences for the fruit yield obtained during the current season. Increasing ethephon doses led to fruit yield reductions in the mandarin ‘Orogrande’ trees in subsequent seasons. When trunk-shaker and ethephon applications were combined, however, yields from the late-maturing orange significantly decline in subsequent seasons. Overall, results show that using a trunk shaker is a viable technique to mechanically harvest citrus trees destined to both fresh and industry market and can be considered as an alternative to the traditional manual harvest usually performed under Mediterranean conditions. However, its use cannot be recommended for late-maturing oranges, such as the ‘Navel Lane Late’ in which mature fruit and fruitlets coexist in the tree at the time of harvest.

scholarly journals Leaf proline accumulation and fruit yield of ‘Pera’ sweet orange trees under natural water stress

Bragantia ◽  
2021 ◽  
Vol 80 ◽  
Author(s):  
Luciana Marques de Carvalho ◽  
Stela Braga de Araújo ◽  
Hélio Wilson Lemos de Carvalho ◽  
Eduardo Augusto Girardi ◽  
Walter dos Santos Soares Filho
Keyword(s):  
Water Stress ◽  
Natural Water ◽  
Sweet Orange ◽  
Proline Accumulation ◽  
Fruit Yield ◽  
Orange Trees

Gas Exchange, Water Relations and Ion Concentrations of Leaves of Salt Stressed 'Valencia' Orange, Citrus sinensis (L.) Osbeck

1987 ◽  
Vol 14 (4) ◽  
pp. 387 ◽  
Author(s):  
J Lloyd ◽  
PE Kriedemann ◽  
JP Syvertsen
Keyword(s):  
Gas Exchange ◽  
Water Relations ◽  
Citrus Sinensis ◽  
Sweet Orange ◽  
Leaf Gas Exchange ◽  
Co2 Assimilation ◽  
Salt Treatment ◽  
Soil Culture ◽  
Co2 Compensation Point ◽  
Valencia Orange

'Valencia' orange [Citrus sinensis (L.) Osbeck] scions grafted on sweet orange [C. sinensis (L.) Osbeck cv. Parramatta sweet orange] rootstock were grown in soil culture under controlled environmental conditions. Salt stress was imposed by adding NaCl to the nutrient solution in increments of 5 mol m-3 per day to a final concentration of 50 mol m-3. Leaf gas exchange, water relations and sodium, chloride and potassium concentrations were monitored until 89 days after commencement of salt treatment. Initial CO2 assimilation rates were relatively low (2.8-4.4 �mol CO2 m-2 s-1) and were stimulated by 72-86% when ambient oxygen partial pressure was reduced from 210 mbar to 21 mbar. After 14 days salt treatment, there was an increase in assimilation rate of approximately 20% associated with a decrease in osmotic potential (π) of 0.6 MPa. Reduction in � occurred without foliar ion accumulation. Assimilation rates gradually declined thereafter, averaging less than 1 �mol CO2m-2 s-1 at day 89. Lower CO2 assimilation rates were not a consequence of increased photorespiration as no change in the extent of oxygen inhibition of CO2 assimilation or CO2 compensation point occurred with salinisation. Stomatal conductance appeared less sensitive to salt treatment than intrinsic photosynthesis, resulting in higher intercellular partial pressures of CO2 in salt stressed leaves (291 cf. 259 pbar for controls at day 89). Water use efficiency was accordingly lower in salt affected leaves. Salinised leaves had consistently more negative osmotic potentials than control leaves; turgor potential was thus maintained at or above control levels for a given bulk-leaf water potential. Since leaf turgor was maintained via osmotic adjustment and uptake of sodium and chloride, lower assimilation rates were attributed to a toxic ion effect.

scholarly journals Quantifying key model parameters for wheat leaf gas exchange under different environmental conditions

2020 ◽  
Vol 19 (9) ◽  
pp. 2188-2205
Author(s):  
Fu-nian ZHAO ◽  
Shuang-xi ZHOU ◽  
Run-yuan WANG ◽  
Kai ZHANG ◽  
He-ling WANG ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Environmental Conditions ◽  
Leaf Gas Exchange ◽  
Model Parameters ◽  
Wheat Leaf

Gas exchange rates at different vapor pressure deficits and water relations of ‘Pera’ sweet orange plants with citrus variegated chlorosis (CVC)

2003 ◽  
Vol 98 (3) ◽  
pp. 233-245 ◽  
Author(s):  
Gustavo Habermann ◽  
Eduardo Caruso Machado ◽  
João Domingos Rodrigues ◽  
Camilo Lázaro Medina
Keyword(s):  
Gas Exchange ◽  
Vapor Pressure ◽  
Exchange Rates ◽  
Water Relations ◽  
Sweet Orange ◽  
Citrus Variegated Chlorosis

Seasonal variation of carbon assimilation in mango (cv. Kensington Pride): effect of flowering treatments

2003 ◽  
Vol 54 (3) ◽  
pp. 309 ◽  
Author(s):  
Alonso González ◽  
S. J. Blaikie
Keyword(s):  
Gas Exchange ◽  
Chlorophyll Content ◽  
Leaf Gas Exchange ◽  
Average Rate ◽  
Carbon Assimilation ◽  
Vapour Pressure Deficit ◽  
Dry Season ◽  
Fruit Yield ◽  
Wet Season ◽  
The Tropics

In the tropics of northern Australia the mango cultivar Kensington Pride exhibits erratic flowering and fruiting and low productivity. Two treatments to manipulate flowering were applied. The first, mango flowering treatment (MFT), involved cutting a cincture through the bark around the circumference of the tree trunk and tying into the cincture a length of twine soaked in a solution of morphactin, CF125. The second involved applying paclobutrazol (PBZ) as a soil drench around the trunk of the tree. Phenology, leaf gas exchange, and fruit yield were assessed over 2 seasons in 3 separate groups of trees in commercial orchards near Darwin.Both MFT and PBZ supported earlier and/or more intense flowering in the season of application than did control trees. The PBZ was re-applied annually and the beneficial effect on flowering occurred in successive years. The MFT was applied once only at the start of the experiment and the effect of MFT was not evident in the second season.The effect of MFT on gas exchange was characterised by a severe reduction in net carbon assimilation (Amax), stomatal conductance (gs), and transpiration (E) for up to 4 months following treatment. Trees receiving PBZ generally had higher rates of leaf gas exchange than MFT trees but similar to control trees. During the dry season, leaves of MFT, control, and PBZ trees had similar rates of Amax. In the year of application, chlorophyll content of MFT trees was lower than that of the other treatments, but in the second year it was very similar to control trees. PBZ trees had the highest chlorophyll content during the study. Commercial fruit yield of PBZ-treated trees was 2–3 times higher than that of control or MFT trees. Independent of the flowering treatments, Amax followed a seasonal trend with an average rate of 9.05 μmol/m2.s (min. 4.42, max. 13.2) during the wet season (January–April), and 4.2 μmol/m2.s (min. 1.11, max. 8.7) during the dry season (May–October). Regression analysis demonstrated that 82% of the variation in gs and 76% of the variation in Amax could be explained by the effect of vapour pressure deficit of the leaf (VPDL) in field-grown mango trees.

scholarly journals Sources and rates of potassium for sweet orange production

2011 ◽  
Vol 68 (3) ◽  
pp. 369-375 ◽  
Author(s):  
José Antonio Quaggio ◽  
Dirceu Mattos Junior ◽  
Rodrigo Marcelli Boaretto
Keyword(s):  
Sweet Orange ◽  
Fruit Yield ◽  
Soluble Solids ◽  
Negative Effects ◽  
Maximum Economic Yield ◽  
Yield And Quality ◽  
Agricultural Use ◽  
Orange Trees ◽  
K Fertilization

Fruit yield and quality of citrus trees (Citrus spp.) is markedly affected by potassium (K) fertilization. Potassium chloride is the major source of K, even though other sources are also available for agricultural use when crops are sensitive to chloride or where potential for accumulation of salts in soils exists. Only few studies addressed the effect of K sources on yield and quality of citrus fruits. Therefore, the present study was conducted to evaluate K2SO4 and KCl fertilizer sources at 0, 100, 200, and 300 kg ha-1 per year K2O on fruit yield and quality of 'Pêra' and 'Valencia' sweet orange trees in the field. The experiments were carried out in a 4 × 2 factorial design under randomized complete blocks, with four replicates from 2001 to 2004. Fruit yield increased with increased K fertilization. Nutrient rate for maximum economic yield of 'Pêra' was 200 kg ha-1 of K2O and for 'Valencia', 270 kg ha-1 of K2O. Differences were attributed to higher production and K exportation by fruits of 'Valencia'. Fruit mass also increased with increased K fertilization what decreased total soluble solids in juice, and which correlated with leaf K concentrations for 'Valencia' (r = 0.76; p < 0.05). Leaf Ca, Mg and B concentrations decreased with K rates. Additionally, leaf Cl increased up to 440 mg kg-1 with KCl rates, even though no negative effects occurred either on fruit yield or quality of trees.

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