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- Author or Editor: Bradford C. Bearce x
Easter lilies (Lilium longiflorum Thunb. `Nellie White') were forced in root media composed of 1 peat: 1 vermiculite (v/v) mixed with coal bottom ash (CBA) at rates of 0%, 25%, 50%, 75%, or 100% CBA. Lilies in all levels of CBA were equal in mean per plant flower bud numbers, fresh and dry weights, and numbers of yellow or brown lower stem leaves. Lilies in 100% CBA were significantly lower in mean stem length than plants in 0% or 50% CBA. Plants in 100% CBA required more frequent irrigation than plants in all other media. Media pH and solution electrical conductivity increased with increase in percent CBA. Analysis of leaf tissue showed no difference in nutrient levels between plants in 0% or 100% CBA.
Poinsettia (Euphorbia pulcherrima Willd. Ex Klotsch) cultivars `Dynasty Red', Nutcracker Pink', and `Annette Hegg Topwhite' were planted in 15-cm azalea pots containing peat: vermiculite (1:1, v:v) in which coal bottom ash sieved through 6-mm mesh was mixed in proportions of 0%, 25%, or 50% by volume. Planting date was 23 July 1996, and pinch date was 25 Aug. Harvest date at anthesis was 16 Dec. Plant heights of all cultivars were increased in the ash media. L, a, and b, values measured with a Minolta CR-200 chroma meter differed very slightly among ash levels within cultivars. Mean per plant bract cluster count was very similar among ash levels and cultivars. Mean diameter of largest bract cluster was increased above that of 0% coal ash plants for `Topwhite' plants in 50% coal ash media. Mean per plant dry weights of all three cultivars were increased over those of control plants in both 25% and 50% coal ash media. Media pH increased with increase in ash, while EC tended to decrease. Media available Ca increased with ash increase, while Mg decreased and the same pattern was noted for leaf tissue Ca and Mg. This was probably due to release of Ca from the ash, which contains about 10% Ca oxides. Tissue levels of Ca and Mg were within acceptable ranges; however, K levels also declined in plant tissue to suboptimal levels with plants in ash media.
Rooting performance was evaluated for three different hydrangea (Hydrangea macrophylla Thunb. `Blaumeise Lace Cap') cutting types in propagation media containing peat:sand amended with 0%, 25%, 50%, and 100% coal bottom ash (CBA) sieved through 2-mm mesh. Electrical conductivity (EC) values of all media were in acceptably low ranges, whereas pH was suboptimal in all but 100% CBA, ranging from 3.8 to 4.6 vs. 6.0 to 6.75 for 100% CBA. Available Ca was significantly higher at up to 189 mg·kg–1 in the 100% CBA. Rooted cuttings were analyzed for root counts and dry mass. Terminal tip cuttings produced 96.1 mean roots/stem compared to butterfly cuttings (76.4) and single-eye cuttings (60.7), and there was no significant difference in root dry mass among the different cutting types. Propagation media containing 50% CBA produced greater numbers of roots/stem (99.89 and 89.59, respectively). The dry mass of roots/stem was significantly higher in media with 100% CBA. Root numbers per cutting were higher in terminal tip cuttings grown in 50% and 100% CBA and butterfly cuttings in 50% CBA. On the other hand, dry mass per cutting was higher in 100% CBA as compared to the rest, except for the terminal tip and butterfly cuttings in 50% CBA. The higher pH and Ca concentration may be factors causing the better rooting performance in 100% CBA.
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.
Easter lilies (Lilium longiflorum Thunb. `Nellie White') were placed at three spacings of about 11, 22, or 44 plants per square meter (plants/m2). Above canopy light intensities, measured weekly at noon, ranged from 107.3 to 704.5 μmol·s–1·m–2 and were not significantly different among spacings. Mid canopy light intensities ranged from 16.5 to 229.0, 43.0 to 458.5, and 77.5 to 535.3 μmol·s–1·m–2 at spacings of 44, 22 and 11 plants/m2, respectively. On February 5, 1996, three plants from the 22 plants/m2 spacing were sprayed with a solution of 0.5 ml·L–1 of 1.8% (a.i.) of each of N-(phenylmethyl)-IH-purine-6-amine and gibberellins A4A7; and on March 5, three additional plants from each spacing were similarly sprayed. Beginning 5 Mar., weekly counts were made of yellow and brown leaves on all treated and control plants. Average per plant numbers of brown leaves increased on control plants at all spacings but increased on treated plants only at the 11 plants/m2 spacing. On 25 Mar., control plants averaged 15.6, 12.1, and 15.3 brown leaves per plant at spacings of 11, 22, and 44 plants/m2, respectively, while plants treated on March 5 averaged 10.7, 9.0, and 10.7 brown leaves. Plants treated on 5 Feb. averaged 3.5 brown leaves per plant and had an average mid leaf length of 13.8 cm compared to about 10.5 cm for all other plants. Spacing had no effect on average yellow or brown leaves per plant. This study demonstrated that early applications of Promalin can reduce leaf senescence which may occur during forcing time before bud appearance to opening of first bud. Some leaf enlargement may occur on plants treated very early.
Dormant budded plants of Hydrangea macrophylla (Thunb.) cvs. Blaumeise Blue and Pink were planted on 29 Jan. 1996 in 15-cm azaleas pots containing media with topsoil, peat, perlite, coal bottom ash, and mine soil, mixed in varying proportions. Media pH levels were initially adjusted with dolomitic limestone to a range of 6.0 to 6.1 for pink inflorescences and with ammonium sulfate to a range of 4.4 to 5.9 for blue inflorescences. Plants of Blaumeise Blue and Blaumeise Pink in low pH media were drenched on 29 Feb. with a solution of aluminum sulfate at 6 g·L–1. Number of shoots per plant were reduced in media with the highest proportion of coal bottom ash (40%, v/v) plus 30% mine soil. Plant diameter was affected very little by type of media. Tallest plants were `Blaumeise Pink' growing in media containing at least 20% top soil or mine soil plus 20% coal bottom ash. These mixes also contained 20% or 40% perlite. Inflorescence diameters ranged from 10.88 to 17.43 cm. and were mostly unaffected by media type. Inflorescence number per plant appeared to be reduced in `Blaumeise Blue' regardless of media. Inflorescence color brightness ranged from L = 55.26 to 61.38 and was affected very little by media type in both cultivars. Bluest inflorescences occurred on `Blaumeise Blue' plants growing in a combination of zero top soil, 40% peat, 30% perlite, 20% coal bottom ash, and 10% mine soil with no lime, and`Blaumeise Pink' plants growing in media with zero topsoil, 40% peat, and 20% mine soil. Blue color did not develop well in media containing top soil and no mine soil. This study demonstrated that florists' hydrangea can be satisfactorily forced in media containing substantial amounts of coal bottom ash and mine soil and that color regulation is also possible in some of these media.
Four poinsettia cultivars were planted in root media containing 0%, 25%, or 50% (by volume) of coal bottom ash or aged hardwood sawdust. Bract color development in `Supjibi' was delayed in media containing sawdust or ash by up to 8–12 days. Bract color initiation of `Jingle Bells' and `Success' occurred earliest in media containing 25% sawdust, but color development was delayed in 50% coal ash. Color development in `Dark Red Hegg' was not affected by ash or sawdust. Analysis of combined leaves from all four cultivars showed Fe levels below normal where media contained sawdust. Leaf Mo concentrations increased with increased media sawdust to above the normal range, but Mn levels were below the normal range in sawdust media. Leaf Ca levels were below normal in all media, possibly due to excessively high K levels in media and leaves. When fertilizer concentration and frequency were adjusted to media EC levels, control media (0% ash or sawdust) required 100 ppm N once a week. Media containing sawdust required 300 ppm to maintain EC levels between 1.25–2.25 dS·m–1 and coal ash media were irrigated with water following the sixth week after planting due to EC levels >2.25.
This study evaluated the effect of reversible water stress on heat stress tolerance (HST) in greenhouse-grown geraniums. Water stress was imposed by withholding irrigation until pots reached ≈30% (by weight) of well-watered (control) plant pots, and maintaining this weight for 7 days. Control plants were watered to just below field capacity, every other day. Leaf xylem water potential (LXWP, MPa), leaf-relative water content (LRWC,%), media water content (MWC, % fresh weight), and heat stress tolerance (HST, LT50) were determined for control and stressed plants. HST (LT50), defined as temperature causing half-maximal percent injury, was based on electrolyte leakage from leaf disks subjected to 25 to 60C. Control-watering was restored in stressed plants and above measurements made after 7 days of recovery. Data indicate: 1) LXWP, LRWC, and MWC in control and stressed plants were –0.378 and –0.804 MPa, 92.31% and 78.69% and 82.86% and 15.5%, respectively; 2) HST increased significantly in stressed as compared to control plants (LT50 of 55C vs. 51C); 3) control plants were near maximally injured by 53C treatment and sustained more than 3-fold greater injury than stressed plants at 53C. In recovered plants, LXWP and RWC reversed back to control levels, paralleled by loss of higher HST.