Kalanchoe × sp. cvs. Mace, Thor, and Telstar were subjected to 2, 3, 4, or 5 weeks of long nights (LN) at 10, 16, or 21°C. The cultivars varied in the number of LN for 100% flowering, and this was influenced by temperature. No temperature was more inductive than 16°C; yet, ‘Thor’ required twice as many LN as ‘Mace’. After 2 weeks of LN the relative growth-rate patterns among ‘Mace’ plants under non-inductive conditions continued, but the patterns of ‘Thor’ and ‘Telstar’ changed. Flowering after 2 weeks of LN averaged 91.7% for ‘Mace’, nil for ‘Thor’, and 25.3% for ‘Telstar’.
Lycopersicon Lycopersicum `Mountain Pride' seedlings were greenhouse grown for 8 weeks in pots of Congaree silt loam amended with 1/8 volume leonardite. They received the recommended rate or half the recommended rate of 5-10-10 granular fertilizer (surface applied) with urea or ammonium sulphate as N sources. Leonardite enhanced plant growth (plant height, fresh and dry weights, stem diameter, and leaf area) only when utilized with a complete fertilizer, regardless of the N source; however, it was more effective with ammonium sulphate than with urea. With ammonium sulphate, the amount of N applied could be halfed if leonardite were added, producing about the same positive results achieved with urea at the full recommended N rate hut without leonardite added.
Leonardite additions (0, 1/16, l/8, 1/4, or 1/3 volume leonardite/volume medium) were more effective if applied only before (Expt. 1) than if applied before and after transplanting (Expt. 2). In Expt. 1, root dry weight (4 weeks after transplanting) of marigold increased 58% to 152% with 1/3 leonardite (by volume) best; zinnia, 15% to 150%, with no differences from 1/8 to 1/3 volume; tomato, a 64% increase at 1/8, a 57% increase at 1/4, and a 47% increase at 1/3 volume, with no differences among 1/8 to 1/3 volume. In Expt. 2, 1/3 leonardite addition inhibited potential root growth. No differences in stem caliber or shoot length or dry weight were found in Expts. 1 or 2. Maxicrop soluble-extract powder seaweed drenches increased roots by ≈21%, as did Maxicrop cold processed seaweed extract liquid (1:500). All extracts were applied 4 times beginning a week after transplanting. The most significant find was a 65% increase in root dry weight and a 7% increase in stem caliber with Maxicrop cold processed seaweed extract drenches (1:200). No differences in shoot length or dry weight were found.
Rooted cuttings of ‘Annette Hegg Lady’ poinsettia (Euphorbia pulcherrima Willd.) were planted in growing media of equal volumes clay loam and sand or ash with 30 or 60% (by volume) pine bark, sphagnum moss peat, perlite, or rubber. Media physical measurements revealed better drainage with 60% perlite during maximum vegetative growth resulted in plants of highest quality: greater aerial fresh weight, increased height, greater inflorescence diameter, and higher grade.
Cut carnation (Dianthus caryophyllus) `White Sim' flowers from Columbia (South America), nontreated or dipped for three seconds in water or 9.5 g/1 benlate (DuPont) or 3336 (Cleary), were placed in “orchid tubes” and remained in air or were packaged in barrier bags of air or 10% CO2/10%O2 (80%N2). Postharvest life (days) was recorded, and the CO2, O2, and CH2=CH2 concentrations within the bags were monitored with gas chromatographs. Controls, nonsealed and in air, did not differ in postharvest life, indicating no benefit from a fungicide dip (P= 0.05). Botrytis was not observed in this test. Flowers sealed in bags did not differ in postharvest life (P= 0.05); however, when a single degree of freedom comparison was made (PR>F: 0.0001), their postharvest life was longer than controls (5.8 vs. 3.1 days). In bags, CO2 increased and O2 decreased over time, CO2 remaining higher and O2 lower with the 10%CO2/10% O2 treatment. CH2=CH2 increased to 4 ppm over 10 days, but ppm within bag treatments did not vary on any day (P= 0.05).
The packaging of flowering Phalaenopsis sp. orchids in sealed plastic film offers potential advantages of extending shelflife and maintaining quality by slowing respiration and protection from the hazards of retail distribution. Following treatments, 2-year-old plants, each with three to nine open florets, were stored at 21 to 27C for 76 days under natural light and natural daylengths. Plants were sealed individually in bags of air, or in bags of initially 15% O2, 23% CO2, balance N,, or 20% O2 and 30% CO2. Control plants were left in open air and were watered twice weekly; plants in sealed bags were not watered. Gas concentrations in the sealed bags were monitored twice weekly. The various atmospheres had no effect on floret life. Two distinct patterns of O2 and CO2 variation with time were observed, but inflorescence half-life values were not related to these patterns. Florets on plants in bags had a greater incidence of discoloration.
Supplemental night lighting of Easter lily (Lilium longiflorum Thunb) plants (2, 5-7) induces early floral initiation and reduces the number of leaves per plant, provided the bulbs (plants) have not been saturated with cold inductive temperatures <21.1°C, the upper limit of vernalization for Lilium ‘Ace’ (6). Also, ‘Ace’ bulbs respond to light during cold storage, which reduces the number of leaves formed before floral initiation and increases the percentage of plants that flower (4). Lighting Allim bulbs during cold storage was also shown by De Mille and Vest (1) to promote early flowering.
Leaves of chilled `Moss-Agate' Episcia (Mart.) plants exhibited direct chilling injury (i.e., watersoaked browning of leaf blade interveinal areas within 24 h of exposure to low temperature) immediately following exposure in darkness to 10C for 0.5 or 1.0 h. Chlorophyll fluorescence peak: initial ratios and terminal: peak ratios of chilled Episcia were -reduced 20% and 25%, respectively, 3 h after chilling, a result suggesting possible photosystem II damage. Total leaf chlorophyll content was reduced by 17% within 3 h of chilling and CO2uptake also was reduced at this time. Leaves of chilled `Rudolph Roehrs' Dieffenbachia maculata (Lodd.) (D. Roehrsii Hort.) plants expressed no visible injury within 24 h of 1.2C chilling in darkness for 36,48, or 60 h, but CO2uptake was reduced by 70% compared to the control 3 h after chilling. Visible injury began to appear 27 h after chilling, and the older leaf blades of all chilled plants exhibited a watersoaked appearance 75 h after chilling. Chlorophyll fluorescence peak: initial ratios of chilled Dieffenbachia did not vary, and terminal: peak ratios were not reduced until 147 h after chilling, when the injured tissue was extremely flaccid and translucent. Chilling reduced the chlorophyll content of Dieffenbachia by 10% in some plants 27 h after chilling and by 35%. in all plants 75 h after chilling. Transpiration rate was reduced and stomata] diffusive resistance increased 27 h after chilling.
New Mexico-mined raw leonardite was characterized by comparing it with the International Humic Substances Society's Standard Leonardite. In the first experiment, adding as little as 1/64 leonardite (v/v) to a sand medium increased tomato [Lycopersicon esculentum (L.) Mill. `Mountain Pride'] root and shoot growth compared with plants produced with fertilizer alone. Growth increased linearly with increasing leonardite levels, from 0% to 25%; however, 50% leonardite inhibited growth. In a second experiment, leonardite alone had no effect on plant height, shoot or root fresh and dry weight, or total leaf area, but stimulated growth when combined with a complete fertilizer. Adding 1/3 leonardite (v/v) (the highest level) and a complete fertilizer increased plant height 40%, total leaf area 160%, shoot fresh weight 134%, root fresh weight 82%, shoot dry weight 133%, and root dry weight 400%.