Some effects of copper and boron deficiencies on the growth and flowering of chrysanthemum morifolium (cv. hurricane)

The effects of copper and boron deficiencies on spray chrysanthemums (cv. Hurricane) have been studied in a peat‐sand substrate. Severe copper deficiency prevented bud initiation and development; the lateral shoots, if present, elongated and produced numerous bracts and leaves. In these respects the deficiency simulated the effects of continuous long day treatment, but differed by causing collapse and death of the lower leaves. Less severe deficiency of copper greatly delayed flowering, reduced the size of the sprays and the numbers of flowers per spray, and rendered much of the crop unsaleable. Boron deficiency caused some quilling of the petals but had relatively little effect on other aspects of growth and flowering in these experiments. Where copper deficiency was not severe, however, omission of boron and copper together affected flowering more than did either deficiency alone. Possible explanations of this interaction are discussed. Analytical data for boron and copper in the foliage are tabulated.