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Experiments were conducted to investigate the effects of dif-
ferent concertrations of calcium nitrate treatments on the
growth and development,nutrition, stem strength and plant
morphology of poinsettia(Euphorbia plucherrima Willd. ex
Klotzsch) cvs. Supjibi, Peter Star and Angelika. Results
indicated that different concentrations of calcium nitrate
treatments on the height, width, leaf number, total leaf area
and vegetable growth were not significant, however they
appeared to be coincide with increased concentration of Ca(
NO3)2 applied to 'Angelika' poinsettias. No significant
difference of treatments on the total inflorescence diameter,
bract number, total bract area and bract color( including
lightness, value of a and b, hue and saturation) of the three
cultivars. Leaf P and Ca contents are lower than that of bract
after treatment of different concentration of calcium nitrate,
but leaf N, Ca and Mg contents are higher than that of bracts.
Both of Cu and Zn contents were in deficiency range. Leaf Ca
and Mg contents were higer than those the of stems,but both
leaf and stem K contents were similar. Free and bound calcium
in leaves was higer than that in bracts and stems. The
transpiration and stomatal conductance of 4th, 5th and 6th
leaves of cv. Supjibi treated with 800 ppm Ca(NO3)2 showed the
highest one. Stem strength, break intension, trail, jelly and
crisp were fairly corelated to Ca(NO3)2 treatment levels in the
three cultivars. There was no significant difference in plant
morphology of poinsettia in different Ca(NO3)2 treatments.
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