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Abstract
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Ispaghul (Plantago ovata Forsk.) as an
important medicinal plant has obtained a remarkable
reputation due to therapeutic applications of seed
mucilage. To determine the effect of in vitro-induced
polyploidy on various characteristics of P. ovata, the
terminal bud of two true leaves seedlings were
separately treated with colchicine [0.1, 0.3 and 0.5%
(w/v) for 6, 12 and 24 h] and trifluralin [7.5, 15 and
22.5% (w/v) for 24, 48 and 72 h] solutions. The ploidy
level of induced tetraploids was determined via
chromosome counting of root tip cells, and then
confirmed through flow-cytometric analysis. Comparison
the morphological, physiological, anatomical
features of intact diploids and induced tetraploids
revealed that tetraploids had considerable more height,
thicker leaf, larger spike and seed, larger pollen grain
and more seeds per spike. Moreover, the amount of
chlorophyll (a, b, and total) and carotenoids, as well as
chloroplast number in guard cells was further in
tetraploids than diploids. Unlike density, stomata size
in tetraploids was bigger than that one in diploids. It
was also observed that seeds of tetraploids had more
mucilage than diploids. In summary, we firstly
developed the P. ovata tetraploids and suggested
0.3% colchicine for 24 h and 22.5% trifluralin for 72 h
as the optimum treatments for inducing tetraploidy in
P. ovata.
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