Abstract
The cultivation of chrysanthemums originated in China more than 2000 years
ago. Today this flower is regarded as one of the most popular cut flowers in
the world. It is, therefore, important to ensure that high quality flowers are
produced consistently for the local and export markets. Chrysanthemum
morifolium cv. ‘Sunny Reagan’ flowers were grown in a greenhouse sprayed
with an electro-activated sodium bicarbonate solution (anolyte) in an attempt
to improve productivity and postharvest quality. A non-activated sodium
bicarbonate solution was also used to determine the overall effect of sodium
bicarbonate on chrysanthemum plants. Sodium bicarbonate acts to enrich the
environment of the plant with CO₂ thereby increasing its photosynthetic
activity. Anolyte showed a positive preharvest effect on the chrysanthemum
plant by increasing the leaf size and overall quality. On the other hand,
sodium bicarbonate produced low quality plants with fewer flowers than the
control. These plants also exhibited necrotic leaf edges, which is a sign of salt
stress. Anolyte-treated plants exhibited no significant increase in postharvest
longevity. Anolyte treated plants showed an increase in leaf cell size and
density and a decrease in the size of intercellular air spaces, indicating an
improved ability for photosynthesis, whereas, treatment with sodium
bicarbonate resulted in thinner leaves with a smaller midrib and a less
developed vascular system when compared to the control. The chloroplasts
in anolyte-treated plants exhibited an increase in starch grains, also an
indication of enhanced photosynthesis. Anolyte-treated plants also showed
an increase in chlorophyll concentration and an improved CO₂ uptake. It is
clear from this study that anolyte stimulated photosynthesis in chrysanthemum
plants, thus resulting in longer stems with more and larger flowers and leaves.
Prof. C.S. Whitehead