Rooted cuttings of `Supjibi' poinsettia were potted in peat vermiculite, mixed with coal bottom ash at 0%, 25%, 50%, 75%, or 100% by volume. Values of pH were higher in media containing coal bottom ash. In general, pH increased for the first 4 weeks, during which time 50–100 ppm (N) fertilizer was being applied, decreased temporarily when 200 ppm fertilizer began, and then increased and stabilized for the last 5 weeks. At first, pH tended to be higher with increase in ash, but when 200 ppm fertilizer was begun, pH became the same in all coal ash levels. Once fertilization was stopped, pH tended again to be higher in ash media. Levels of EC remained low in all media when 50–100 ppm of fertilizer was applied, but increased after 200 ppm fertilizer was begun, increasing to excessive levels 2 weeks later. With more watering, EC declined in the 0% ash, but remained high in 50% to 100% ash media. Leaf Ca content increased with increase in media ash but was below the normal range in all plants. With increase in media ash, water capacity decreased, but bulk density increased. Bract color development in plants in ash media appeared delayed.
Petunia and impatiens seedlings were planted in cell packs containing 0%, 25%, or 50% (by volume) coal bottom ash (CBA) mixed with peat: vermiculite. High soluble salts caused fresh and dry weights to be greatly reduced in 25% and 50% CBA. This was thought to be due to insufficient drainage in the shallow cell packs. Subsequent crops were grown in 4-inch pots. Double Pink impatiens in 4-inch pots showed no significant difference between control and ash media in the number of buds and flowers, plant heights and diameters, and fresh and dry weights. For `Mixed Shady Lady' impatiens, the number of flowers, and fresh and dry weights were greater in the control and 50% CBA. Plant heights were reduced in 25% and 50% CBA media. There were no differences in plant diameters among the media. Ivy geraniums showed no significant difference in the number of days from planting to first bloom and 50% florets opening; number of florets, buds, and inflorescences; and stem lengths. Shoot numbers were reduced in 25% and 50% CBA. There was also no significant difference in number of days from planting to first bloom and 50% florets opening, or number of buds and inflorescences for zonal geraniums. Number of florets increased for zonal geraniums in 25% CBA.
A recycling nutriculture system was redesigned to improve growth and flowering of Tagetes erecta L., cv., Inca Yellow in four media; loose rockwool (RW), coal bottom ash (CBA), pinewood peelings (PWP) and CBA:PWP (1:1, v/v). Three nutricycle frequencies of 12, 6 and 4 per 12 hour light period were set with a nutricycle duration of 5 minutes. Volume, height and fresh and dry weights of marigolds in CBA, PWP and CBA: PWP were comparable to that of marigolds in RW. Flower diameters of plants in CBA, PWP and CBA:PWP were increased and days to harvest decreased compared to plants in RW. Plants in CBA: PWP increased in fresh weight compared to CBA or PWP plants. No interaction occurred between media and nutricycle frequency at 12 or 4 cycles per 12 hours; however a malfunctioning timer caused prolonged flooding of plant root zones at the 6 cycle setting. This resulted in decreased plant volume and fresh and dry weights at this frequency. These results show that growth and flowering of marigolds in CBA and PWP comparable with that in RW can be achieved with more than 1 nutricycle frequency.
Rooted cuttings of `Dark Red Hegg' poinsettia were potted in root media containing 0, 50, or 100 percent by volume of coal bottom ash in peat::vermiculite (50:50, v/v), one cutting per 1 liter pot. The plants were placed in a closed loop nutriculture system and irrigated with 200 mg N.liter-1 of (N-P-K) 20-8.8-17.8. 15-2.2-22.25. or 20-4.8-21.6 (commercial Hydrosol + Ca(NO3)2). each with soluble trace elements. Fertilizer solutions were maintained at pH=6.0-6.5 and E.C.=1.6-2.5 dS.m-1. Media pH and E.C. tended to increase with amount of ash in the media. The 20-8.8-17.8 fertilizer reduced pH values 0.6-0.8 in all media. Plants were of equal height in all media. Average bract cluster diameters of plants in 100 percent coal ash were reduced compared to those in 0 and 50 percent coal ash by the 15-2.2-22.25 fertilizer. but not by the other two fertilizers. Plant top dry weights in 100 percent ash were reduced below those in 0 and 50 percent ash by the 20-8.8-17.8 and the 15-2.2-22.25 fertilizers.
A 0.2-ha reclaimed minesoil site near Welch, W.Va., was amended with sewage sludge, hardwood bark, and a sorghum–sudan hybrid green manure crop to demonstrate production of horticultural crops. A selection of crops, including white birch, forsythia, zinnia, tomato, yarrow, red raspberry, and strawberry, was planted and grown. Plant growth and development, including flower and fruit production, tended to be enhanced by sludge-amended soils and reduced in green manure and hardwood bark–amended soils. Sludge increased pH, Ca, P, and Mg levels above that in the other treatments. Hardwood bark increased Mn but decreased P. The green manure amendment increased soil Fe content. In 1994 `Allstar' strawberry yield and berry weights were similar for all plots, but yield was about 10% of expected and was very close to the economic break-even point. Third-year yield of 1992 planted `Heritage' raspberries was about one-half the expected yield of 5000 lbs/acre, but still considered profitable. Zinnia flower production yielded a calculated 32% return on investment. Assuming that 50% forsythia plants were saleable in 2 years, return on investment was projected to be 30%. For white birch, assuming half were saleable in 4 years, a 16% return on investment was projected.
Evidence is accumulating in favor of a linkage at the cellular level between various abiotic stresses. We conducted a study to evaluate the effect of water stress on the heat tolerance of zonal geraniums. Water-stress was imposed as previously described. Leaf water potential (LWP, MPa), relative water content (RWC, percent), and heat-stress tolerance (HST; LT50, defined as temperature causing half maximal percent injury based on electrolyte leakage) were measured in control, stressed, and recovered (watering restored as in controls) plants. Proteins were extracted from the leaves following the treatments. SDS-PAGE and immunoblotting were performed using standard procedures. Immunoblots were probed with antibodies to dehydrin (T. Close) and 70-kDa heat shock cognate (HSC 70 of spinach) proteins (C. Guy). Data indicate that 1) LXWP and RWC in control and stressed plants were –0.378 and –0.804 MPa and 92.31% and 78.69%, respectively; 2) stressed plants exhibited a significant increase in HST compared to control (LT50 of 55°C vs. 51°C), which was associated with the accumulation of several heat-stable, dehydrin proteins (26 to 50 kDa), and of cytosolic and ER luminal (BiP) HSC 70 proteins; 3) in recovered plants, LXWP, RWC, and HST reversed back to the levels of control concomitant with the disappearance or reduction of dehydrins and HSC 70 proteins. These results suggest that specific stress proteins may play a role in development of heat stress tolerance.
`Inca Yellow' marigolds (Tagetes erects L.) were planted in polyethylene bags containing coal bottom ash (CBA), pine wood peelings (PWP), a mixture of 1 CBA: 1 PWP (v/v), and loose Grodan rockwool (RW) and grown in a circulating nutriculture system. Three fertigation frequencies of 12, 6, or 4 cycles per 12-hour light period were set with a duration of 5 minutes each. Flower diameters of marigolds grown in CBA, PWP, and CBA-PWP exceeded flower diameters of RW-grown marigolds, and days from planting to harvest were less in CBA and CBA-PWP than in the other two media. There was no interaction between medium and fertigation frequency. Foliar analysis showed no significant differences in plant elemental composition among root media or fertigation frequencies. Postharvest PWP water extracts contained higher P levels than extracts of other media, and CBA-PWP water extracts contained higher K, Ca, and Mg. In the CBA-PWP mixture, decomposition products from PWP may have increased P volubility and solubilized the K, Ca,-and Mg-in CBA.