During two successive seasons, complete randomized design experiments
were conducted under natural conditions in plastic house on one-year-old
Chlorophytum comosum (Thunb) Jaques "Variegatum" plants to:
(1) study the effect of Ca (as calcium hydroxide), P (as treble superphosphate, 48%
P20s), F (as sodium fluoride) and B (as boric acid, 17% B) on the leaftipburn in
Chlorophytum. The rates were 0, 2, 4 and 6 g/l. of medium for Ca and P; 0, 3, 6 and 9
mgll. F in solution and 0,5,10 and 15 mgll. Bin solution. Plants were grown ina
mixture of 1 soil : 1 peat : 1 perlite (by volume) or in sphagnum peat moss. Ca
significantly raised the pH and reduced the leaf tipburn area in both media. P
significantly reduced the pH of the mixture and raised it in sphagnum peat, but did not
reflect a consistent effect on the leaf tipburn. F significantly raised the pH both media
in the 1 st season and did not affect the leaf tipburn. At 10 and 15 mgll. B the pH of
both media was significantly reduced, while the burning of the tip on the oldest leaves
was significantly developed with increasing B rates. The concentrations of the tested
elements in the leaf tissues showed an increasing trend with increasing elements in
the medium. As B accumulation increased in the oldest leaves, the tipburn area
increased. Leaf tissues of every treatment contained Na which may be related to the
lamina tipburn.
(2) study the B distribution through the plant foliage using plants grown in
sandy culture treated with (a) a complete Hoagland and Arnon' solution; (b) a second
without B or (c) a third containing 20x the recommended amount of B. With increasing
B amount in the solution the B leaf tissue content and the tip burn area on the oldest
leaves were increased. The uppermost leaves did. not exhibit lamina tipburn. B
accumulation in the oldest leaves was more than that in the uppermost ones. B
distribution in the various parts of the oldest leaves was not uniform and most of B
accumulated in the distal parts, which resulted in the appearance of tipburn on it.