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[ABSTRACT] Effects of container soil level, fertilization,
planting time and disbudding on lotus (Nelumbo) growth were evaluated
in container production. Container soil volume influenced EC,
pH, plant growth indexes, and plant nutritional contents. The
¼ and ½ soil levels were more efficient than ¾
soil level for lotus production in containers. Fertilization
significantly increased plant growth and also influenced plant
nutrient contents. Fresh underground weight, propagule number,
expanded internode number, and emerging leaf number of lotus
grown in 29 liter containers linearly increased with increased
fertilizer rates from 0 to 8 g of ProoSol 20-10-20 per pot and
then leveled off at 12 g rate. There was no effect on plant height
and flower number by fertility treatment. Fertilization also
increased N, P and K and decreased Ca content in young leaves.
Soluble fertilizers (ProoSol 20-10-20, Miracle-Gro 24-8-16 and
15-30-15) were more efficient for lotus growth than both urea
and controlled release fertilizer (Polyon 18-6-12). Miracle-Gro
15-30-15 (higher P rate) was more beneficial for rhizome or propagule
production of lotus. Miracle-Gro 24-8-16 and ProoSol 20-10-20
were favorable for flower production. Flowering peak of lotus
was influenced by the type or composition of fertilizers. Optimum
container fertilization of lotus depends on cultivar, growth
stage, fertilizer type and rate, container size, soil amount
and water volume. Lotus growth was largely affected by planting
time and disbudding. Lotus potted in March and April performed
best, while plants planted in February and May performed worst.
Flower number was generally not influenced by planting time but
flowering peak was different among treatments. Disbudding increased
fresh underground weight and propagule number. Positive relationships
were observed among emerging leaf number, fresh underground biomass,
and propagule number. Propagules could be stored in the cooler
(4 ºC, 95% RH) over 45 days. Gum acacia, sphagnum-moss and
Terra-Sorb® hydrogel had no effects on moisture and viability
of stored lotus propagules. Successful surface sterilization
and sanitation were critical. Optimization of tissue culture
protocol for commercial production of herbaceous peony was also
investigated. Young stem segments were most favorable for callus
induction. Adventitious shoots did not develop from callus and
were only generated on apical or axillary meristematic regions.
Young nodal stems and dormant-released buds were most suitable
for shoot induction. TDZ was more effective than BA for shoot
induction. Gibberellic acid (GA3) had positive effects on explant
growth, shoot induction and stem elongation. Plantlets rooted
in IBA-containing medium or in PGR-free medium following a short
pretreatment with high-concentration IBA.
Full Dissertation |