GROWTH AND LEAF PHOTOSYNTHESIS OF LILIUM LONGIFLORUM THUNB. ‘NELLIE WHITE’ IN RESPONSE TO PARTIAL DEFOLIATION AFTER ANTHESIS

Container-grown ‘Nellie White’ Easter lilies with 45 leaves were defoliated after anthesis to maintain the apical 10, apical 20 or basal 20 leaves.
Bulb weight decreased with decreasing leaf area.
The apical 10 and basal 20 leaves resulted in similar amounts of dry matter gain in the bulbs.
Net photosynthesis (PS) of the apical 5th leaf was unaffected by partial defoliation.
PS of lily leaves reached light saturation at a photosynthetic photon flux (PPF) of 700 μmol/m²/s and was 85% of that rate at 200 μmol/m²/s.
Field-grown plants averaging 70 leaves were defoliated acropetally to maintain the apical 10, 20, or 40 leaves, representing 25%, 50% and 65% of the original leaf area, respectively.
Control plants remained intact.
Dry matter accumulation in mother scales was reduced in plants having the apical 10 and 20 leaves when compared to intact plants.
Dry matter gain in the daughter bulbs remained unchanged until the basal 60 leaves were removed (apical 10 remaining). Weight of stem bulblets, however, was markedly reduced by partial defoliation.
Averaged contribution of the apical leaves to dry matter accumulation in scales (mg dry matter gain/cm² leaf area) was greater than that of the basal leaves.
These results suggest that maintenance of apical leaves to be crucial for continued bulb growth in field-grown Easter lilies.

V International Symposium on Flower Bulbs

Y. Wang

https://doi.org/10.17660/ActaHortic.1990.266.25