CaCl2 Applications Research Articles

Fruit Quality at Harvest of “Jonathan” Apple Treated with Foliarly-Applied Calcium Chloride

The response of “Jonathan” apple trees (Malus domestica, Borkh.) grafted on EMLA 111 to frequent application of calcium chloride (CaCl2) was studied at Topeka, Emporia, and Conway Springs, Kansas, orchards in 2002. Trees were sprayed one to eight times with foliar applications of calcium chloride at the rate of 8.971 kg ha−1. First spray was made when fruits were 1.4, 0.9, and 1.6 cm diameter at Topeka, Emporia, and Conway Springs, respectively. More than six applications of CaCl2 improved fruit quality at harvest. Improvement included an increase in fruit weight, size, appearance, skin redness, and reduction of scald incidents. Although CaCl2 applications had no effect on percent of soluble solids, the ratio of soluble solid content to titratable acidity was increased by frequent CaCl2 application. Fruit skin redness was the most improved quality of “Jonathan” apple as the result of CaCl2 applications. No symptoms of fruit russetting or leaf scalding resulting from frequent CaCl2 application were observed. Increase in fruit quality was attributed to a linear increase in Ca concentrations in fruit and leaf tissues. Increase in Ca concentrations in fruit and leaf tissues of treated trees coincided with increases in potassium (K), magnesium (Mg), phosphorus (P), and nitrogen (N) concentrations compared with untreated control trees. Potassium, Mg, P, and N were correlated with fruit quality as much as, or in some cases more than, Ca. This information suggests that changes in mineral balance with CaCl2 applications contributed to improvement of fruit quality and is evidence that frequent Ca application improved “Jonathan” apple quality in Kansas.

Fruit Quality at Harvest of ?Jonathan? Apple Treated with Foliarly-Applied Calcium Chloride

Abstract The response of “Jonathan” apple trees (Malus domestica, Borkh.) grafted on EMLA 111 to frequent application of calcium chloride (CaCl2) was studied at Topeka, Emporia, and Conway Springs, Kansas, orchards in 2002. Trees were sprayed one to eight times with foliar applications of calcium chloride at the rate of 8.971 kg ha−1. First spray was made when fruits were 1.4, 0.9, and 1.6 cm diameter at Topeka, Emporia, and Conway Springs, respectively. More than six applications of CaCl2 improved fruit quality at harvest. Improvement included an increase in fruit weight, size, appearance, skin redness, and reduction of scald incidents. Although CaCl2 applications had no effect on percent of soluble solids, the ratio of soluble solid content to titratable acidity was increased by frequent CaCl2 application. Fruit skin redness was the most improved quality of “Jonathan” apple as the result of CaCl2 applications. No symptoms of fruit russetting or leaf scalding resulting from frequent CaCl2 application were observed. Increase in fruit quality was attributed to a linear increase in Ca concentrations in fruit and leaf tissues. Increase in Ca concentrations in fruit and leaf tissues of treated trees coincided with increases in potassium (K), magnesium (Mg), phosphorus (P), and nitrogen (N) concentrations compared with untreated control trees. Potassium, Mg, P, and N were correlated with fruit quality as much as, or in some cases more than, Ca. This information suggests that changes in mineral balance with CaCl2 applications contributed to improvement of fruit quality and is evidence that frequent Ca application improved “Jonathan” apple quality in Kansas.

Effects of calcium chloride on apple fruit quality of trees grown in calcareous soil

Two experiments were conducted to investigate effects of application rate and timing of calcium chloride (CaCl2) on fruit quality and control of physiological disorders in ‘Red Delicious’ apple (Malus spp.) grown at five locations in Iran. In first year, the experiment was conducted with three application rates (0, 1%, and 2% CaCl2, w/v) at two application times for each rate. In second year, four rates of CaCl2 (0, 0.5%, 1%, and 1.5%, w/v) were applied, and each rate was applied four times. Fruits were kept in regular atmosphere storage at 2°C for 4.5 months. All CaCl2 treatments, except 0.5% treatment in second year, enhanced fruit firmness at harvest and after storage and resulted in fewer physiological fruit disorders because of higher fruit Ca. Other fruit quality traits and mineral nutrients were not affected by CaCl2 applications. Calcium chloride at 1 % application was optimum for improving fruit quality.

The Role of Calcium and Nitrogen in Postharvest Quality and Disease Resistance of Apples

In several experiments, strong negative correlations were found between fruit and leaf N vs. fruit color and fruit N vs. firmness, but a positive correlation existed between fruit Ca vs. firmness in apples. Based on these relationships, several models were developed to predict postharvest quality using preharvest nutrient status. Quantity and timing of N application to produce optimum-quality fruit in `Delicious', `Fuji', and `Gala' apples have also been investigated. High levels of nitrogen adversely affected fruit quality and increased endogenous ethylene and respiration. In separate experiments, the effects of seven post-bloom CaCl2 applications on various postharvest pathogens were studied in four apple cultivars. Calcium applications did not increase fruit Ca sufficiently enough to reduce colonization or maintain firmness after 4 months of 0C storage, but did slightly reduce infection by these pathogens during the growing season.

Calcium-related Leaf Necrosis of Seedling Carrots

Abstract Seedlings of carrot (Daucus carota L.) develop leaf necrosis when subjected to conditions which encourage rapid growth in controlled-environmental chambers. Necrosis occurred on the 4th and 9th developing leaves and was apparent as they unfolded. Injury was determined to be calcium-related, since foliar CaCl2 applications reduced injury and covering the plants during the dark period to promote translocation of Ca by root pressure flow stopped injury completely. Young unfolding leaves in covered plants had 50% greater Ca concentrations than those plants maintained in the chamber without covering. Carrot cultivars had different degrees of sensitivity to the leaf necrosis with ‘Red Core Chantenay’ > ‘Danvers’ > ‘Carousel’ > ‘Scarlet Nantes’.

Rhizosphere salinity and phytoalexin accumulation in soybean

Rhizosphere salinity decreased the capacity of soybean to accumulate a pterocarpanoid phytoalexin (glyceollin) in the stem in response toPhytophthora megasperma var.sojae. Rapid (48h) accumulation was depressed by NaCl, Na2SO4, CaCl2 and MgSO4 applications. Time-course accumulations was slowed by applications. Time-course accumulation was slowed by application of 0.131M NaCl. Glyceollin accumulation was also reduced in plants subjected to a period of high salinity stress (0.177M NaCl, 72 h) after a period of nonsalinized growth. Calcium chloride completely suppressed glyceollin accumulation in normally-resistant plants but no susceptibility to the fungus was observed.