ISHS Acta Horticulturae 177: IV International Symposium on Flower Bulbs
EFFECT OF CALCIUM ON TIPBURN OF LILIUM 'PIRATE' |
| Author: | J. Berghoef |
| Abstract:
A typical kind of tipburn is observed in Lilium 'Pirate'. Leaves of the upper part of the plant have white-grey cross bands about 2 cm from the tip caused by collapse of one layer of palisade parenchyma cells just under the epidermal layer. Symptoms become visible before the flower buds can be seen, usually when the plant has reached a length of 30 to 40 cm. A high relative air humidity increases tipburn. Plants grown without stem roots also show more symptoms. Removal of the lower leaves just after unfolding decreases tipburn. Severe tipburn is found on plants grown in hydroculture with a low calcium concentration in the nutrient solution. Higher concentrations of calcium decrease tipburn, but can not prevent it. Tipburn decreases when plants are repeatedly sprayed with solutions of calciumchloride or calciumnitrate just before the susceptible stage. In most cases 68 mM CaCl2.2H2O reduced tipburn to an acceptable level. In some cases concentrations up to 204 mM are required, which, however, may damage the leaves and cause browning of the tips. Not only calcium, but also strontium and manganese are effective. This indicates that instability of cell membranes is the cause of tipburn. | |
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