:

3 Calx . 1807 Davy. Knop 1860 . . :

4 : . .

.3

. . . - ATPase NAD-Kinase 6

:Blossom End RotCracking fruitsTipburn in lettuceBitter pit in apples .

7

:PoinsettiaTulip :RosesGerbera8

Blossom End Rot5

Tip burn10

Bitter Pit11

Cracking fruits12

Poinsettia Bract necrosis13

Poinsettia Bract necrosis14Herbaugh and Woltz, 1989 Herbaugh and Woltz, 1986

Poinsettia Lateral Stem Breakage15

Tulip16

Tulip17Nelson and Niedziela, 1998 a Nelson and Niedziela, 1998 b Nelson et al., 2003

Cut roses18

Cut roses19Ganmore-Neumann and Davidov, 1993

Cut roses20Torre et al., 2001

Cut roses21Torre et al., 1999+ Ca- Caba

Gerbera22 .

Gerbera23Gerasopoulos and Chebli, 1999

32 : / .

Atiyeh, R. M.; S. Lee & C. A. Edwards. 2002. The influence of humic acids derived from earthworm-processed organic wastes on plant growth. Bioresearch Tech. 84:7-14Bidegain, R. A.; M. Kaemmerer; M. Guiresse & M. Hafidi. 2001. Effect of humic substances from composted or chemically decomposed polar sawdust on mineral nutrition of ryegrass. J. of Agri. Sci. Cambridge. 134: 259-267Chunhua, L.; R. S. Cooper & D. C. Bowman. 1998. Humic acid application affects photosynthesis, root development and nutrition content of Creeping Bentgrass. Hortscience, 33(6): 1023-1025Cooper, R. J.; L. Chunhua & D. S. Fisher. 1998. Influence of humic substances on rooting and nutrient content of creeping bentgrass. Crop Science. 38: 1639-1644Delfine, S; R. Tognetti; E. Desiberio & A. alvino. 2005. Effect of foliar application of N and humic acids on growth and yield of durum Wheat. Agron. Sustain. Dev. 25: 183-191Gerasopoulos, D. & B. Chebli. 1999. Effects of pre- and post harvest calcium application on the vase life of Gerbera. J. of Hort. Sci. and Biotech. 74(1): 78-81Gislerod, H. R. 1999. The role of calcium on several aspects of plant and flower quality from a floricultural perspective. Acta Hort. 481: 345-352

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Hartwigsen, J. A. & M. R. Evans. 2000. Humic acid seed and substrate treatments promote seedling root development. HortScience: 35 (7): 1231-1233Hepler, P. K. 2005. Calcium: a central regulator of plant growth and development. The Plant Cell. 17: 2142- 2155Mencarelli, R.; R. Agostini & R. Botandi. 1995. Ethylene production, ACC content, PAL and POD activities in excised sections of straight and bent gerbera scapes. J. of Hort. Sci. 70 (3): 409-416Nardi, S. 2002. Physiological effect of humic substances on higher plants. Soil Biology and Biochem. 34: 1527-1536Nardi, S.; D. Pizzeghello; C. Gessa. 2000. A low molecular weight humic fraction on nitrate uptake and protein synthesis in maize seedlings. Soil Biology and Biotechnology. 32: 415-419Panuccio, M. R.; A. Muscolo & S. Nardi. 2001. Effect of humic substances on nitrogen uptake and assimilation in two species of Pinus. J. of Plant Nutrition. 24(4&5): 693-704Pilanali, N. & M. Kaplan. 2003. Investigation on the effect on nutrient uptake of humic acid applications of different forms to Strawberry plant. J. of Plant Nutrition. 26 (4) :835-84334

Pizzeghello, D; G. Nicolini & S. Nardi. 2002. Hormone- like activity of humic substances in different forest ecosystems. New Phytologist. 155:393-402Quaggiotti, S. 2004. Effect of low molecular size humic substances on nitrate uptake and expression genes involved in nitrate transport in Maize. J. of Experimental Bot. 55 (398): 1-11Rudnicki, R. M. 1976. Vase life of Gerbera jamesonii Bolus cut flowers depending upon media, mineral nutrition , their morphological attributes and treatment with flower preservatives. Acta Agrobotanica. 29: 289-296Savvas, D & Gizas, G. 2002. Response of hydroponically grown gerbera to nutrient solution recyclingg and different nutrient cation ratios. Scentia Hort. 96: 267-280Sano, T.; T. Higaki & K. Handa. 2006. Calcium ions are involved in the delay of plant cell cycle progression by abiotic stresses. FEBS Letters: 580: 597-602Starkey, R. K. & A. R. Pederson. 1997. Increased level of calcium in nutrient solution improves the post harvest life pot Roses. J. Amer. Soci. Hort. Sci. 122: 863-868Syros, T.; T. Yupsanis & M. Omirou. 2004. Photosynthetic response and peroxidases in relation to water and nutrient deficiency in gerbera. Environmental and Experimental Botany. 52: 23-31

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**Tip of young roots where the walls of endodermis cells are still unsuberized*Very small amounts in Phloem

*Very small amounts in PhloemHigh RH reduce Ca movement to meristemic tissue creating a Ca deficiency in the growing tips of plant tissueIn the cell wall it binds with free carboxyl groups of pectines.*act as a cement between adjacent cell walls

*Calcium deficiency symptoms appear initially as generally stunted plant growth, necrotic leaf margins on young leaves, and eventual death of terminal buds and root tips. Plant damage is difficult to reverse, so take corrective action immediately. Make supplemental applications of calcium nitrate at 200 ppm nitrogen. Test and correct the pH if needed because calcium deficiency is often associated with low pH.

*bract necrosis/Bract Edge BurnThis disorder, which can be recognized by brown bract margins and eventual internal necrosis, and also referred to as bract burn occurs most frequently on the varieties 'Gutbier V-14 Glory' and 'Supjibi'. Generous fertilizer applications, particularly ammonium sources of nitrogen, continued into the late stages of the season, seem to increase the likelihood of bract burn. Research also has shown increased incidence of the problem when calcium was deficient. Excess soluble salts in the growing substrate causing root injury, reduced water absorption or stress from inadequate or excessive irrigation, damage from pesticides or pollutants, and high relative humidity are also associated with the disorder. Perhaps the greatest damage caused by bract necrosis in the increased chance for Botrytis infection of the damaged tissue, and then the need to control this persistent disease. The following suggestions have been made: Reduce fertilizer rates and frequencies as the crop matures. Primarily use nitrate nitrogen, rather than fertilizer high in ammoniacal nitrogen. Apply adequate amounts of calcium (calcium levels of 0.5% or less in the leaves are considered to be deficient). Consider supplemental calcium sprays (see: Calcium). Do not use excessive amounts of slow-release forms of fertilizer, as nutrients cannot be withheld late in the season. Avoid unnecessary irrigation which can result in soft bracts. Try to avoid high relative humidity. This can be achieved by ventilating and heating late in the afternoon to remove moisture from the greenhouse atmosphere. A policy of not irrigating in the afternoon can also be helpful. Steps taken to reduce relative humidity will not only reduce the incidence of bract necrosis, but will also help control Botrytis if it does occur. Use approved fungicides for Botrytis prevention or control.

**There are several possible reasons for the development of shoots which are so weak and thin that the inflorescences cannot be kept erect without staking. Research has found that cutting quality plays a part in stem breakage. Larger sized cuttings do not tend to break as easily as smaller, weaker cuttings. Early in the production cycle the plants should also be spaced closer together so that the plants will grow more upright. Plants grown with a wider spacing are more likely to produce lateral shoots that can grow out horizontal over the edge of the pot. Support rings will help support the plant and prevent stem breakage, but the cost of the rings and the labor to install them has to be economically justified by the grower. Calcium deficiency also has been reported by some researchers as a cause of weak stems, as calcium is an important constituent of plant cell walls. Varieties can also differ in stem strength with 'Success' and 'Red Splendor' being varieties which are more resistant to breakage. Some of the free-branching varieties produce so many shoots that crowding and reduced light intensity occur. The number of shots can be controlled to a certain extent by limiting the number of nodes below the pinch to 5 or 6 or by the removal of some of the lateral shoots. The first method is practice more often, since pruning can be an expensive operation. Limiting the percentage of ammonical-nitrogen being applied may also help avoid stem breakage. Ammonical-nitrogen promotes vegetative growth that may lead to weaker stem. Since thicker, stronger stems generally result for growth regulator treatments, some growers apply growth regulators to improve stem strength as much as to control height. ***primarily*Injection ca is inconvenient