Articles
EFFECTS OF CARBON DIOXIDE WITH AND WITHOUT NITRIC OXIDE POLLUTION ON GROWTH, MORPHOGENESIS AND PRODUCTION TIME OF POTTED PLANTS.
The investigated plants were Ficus elastica ‘Robusta’, Ficus benjamina, Hedera helix ‘Anne Marie’, Hedera canariensis ‘Montgomery’, Hibiscus rosa-sinensis ‘Moesiana’, Hibiscus rosa-sinensis ‘Red’, Dieffenbachia maculata ‘Compacta’, and Nephrolepis exaltata ‘Bostoniensis’.
Ten to more-than-two-hundred experimental plants of each cultivar were grown during the winter in each of six 41.5 m2 chambers of an experimental greenhouse.
Two chambers served as reference, with no gasses added.
Carbon dioxide was added during the day to a total of 1000 ppm in the other four chambers, and to two of these were at the same time added one ppm nitric oxide.
Starting as young plants in early December, they grew three to five months before being harvested in at least the first of two ways: (a) harvested throughout on a selected day, and (b) harvested successively, as individual plants were saleable.
Carbon dioxide significantly increased the fresh- and dry weight of total aerial parts in two respectively seven of the cultivars by up to 26% and 34% respectively.
With nitric oxide added, only the dry weight of just three cultivars increased.
Morphogenesis of carbon-dioxide-stimulated plants was affected in either of two ways: (a) general stimulation giving longer shoots/taller plants and/or more/larger leaves, or (b) specific increase in number of side shoots.
Nitric oxide inhibited just the same type of morphologic development, which carbon dioxide stimulated.
Production time was affected only when based on a carbon-dioxide stimulated/nitric-oxide-reduced morphologic parameter.
Production time of Hedera helix was significantly reduced with 10% (two weeks) by carbon dioxide, but nitric oxide reduced this advantage by 40%. Other plants were less affected.
Total nitrogen and nitrate-nitrogen content of all young leaves was significantly reduced by CO2-enrichment, on the average by 19% and 45% respectively.
The effect was less with nitric oxide added.
Scorched leaves were only seen in Dieffenbachia maculata, and exclusively in nitric oxide chambers, where 95% of this species had an average of 1.8 leaves damaged, or 23% of their large leaves.