Abstract
In the Table of Contents of the May issue of the Journal the name of L. Daley was misspelled in the listing of the article, Determination of Irrigation and Fertilizer Practices for Jade Plant [Crassula argentea (L.) Thunb.]by J. Spooner, L. Daley, G. Ware, and M. Vines [J. Amer. Soc. Hort. Sci. 103(3):306-308; 1978] due to a printer's error. The name is correctly spelled in the byline of the article itself.
Abstract
Mechanical and chemical methods for improving the branching of Crassula argentea Thunb., Kalanchoe tomentosa Bak., and Columnea microphylla Klotzsch and Hanst. ex Orst. were examined. C. argentea did not respond to hand-pinching, atrinal, or BA treatments. K. tomentosa produced 44% more branches when treated with 50 ppm BA but were relatively unaffected by atrinal or hand-pinching. C. microphylla typically branched only from the basal nodes; however, 59% more branching was observed when treated with 500 ppm atrinal. Hand-pinching or BA did not affect branching of Columnea. Atrinal also retarded stem elongation of C. microphylla; the inhibitory effect of 500 ppm was comparable to the reduction in stem length caused by hand-pinching. Chemical names used: (2,3:4,6 bis-O-(1-methylethylidene)-O-L-xylo-2-hexulofuranosonic acid, dikegulac sodium, atrinal), N-(phenylmethyl)-2H-purin-6-amine (BA).
One cactus and 17 succulent species/cultivars were grown at 10, 16, 22, or 28 °C (plant temperature) for 10 or 15 weeks. The change in leaf/tubercle number at each temperature (after 10 or 15 weeks) was determined, and leaf/tubercle-unfolding rate was calculated. ‘Jade Necklace’ kebab bush (Crassula rupestris ssp. marnieriana), ‘Lola’ echeveria (Echeveria), ‘Green Ice’ gasteraloe (Gasteraloe), and lithops (Lithops species) leaf-unfolding rate per day was unaffected by temperature. Leaf-unfolding rate per day increased as temperature increased from 10 to 16 °C on ‘Firebird’ aloe (Aloe), ‘Key Lime Pie’ adromischus (Adromischus cristatus), prostate rainbow bush (Portulacaria afra variegata), burro’s tail (Sedum burrito), and ‘Sir William Lawrence’ houseleek (Sempervivum calcareum). Leaf-unfolding rate per day increased as temperature increased from 10 to 22 °C on mescal agave (Agave parryi truncata), ‘Firebird’ aloe, Sunrise anacampseros (Anacampseros telephiastrum variegata), ponytail palm (Beaucarnea recurvata), subsessilis echeveria (Echeveria subsessilis), zebra plant (Haworthia fasciata), prostrate rainbow bush, burro’s tail and ‘Sir William Lawrence’ houseleek. Increasing temperature from 22 to 28 °C decreased ‘Kiwi’ tree houseleek (Aeonium percarneum) leaf-unfolding rate per day, increased ‘Firebird’ aloe and tiger tooth aloe (Aloe juvenna) leaf-unfolding rate, and resulted in shoot tip death on burro’s tail, and plant death of ‘Sir William Lawrence’ houseleek and ‘Silver Dollar’ jade (Crassula arborescens). The cactus, ‘Arizona Snowcap’ mammillaria (Mammillaria gracilis fragilis), tubercle-unfolding rate per day increased as temperature increased from 16 to 28 °C. Taken together, temperature (10 to 28 °C) effects on development rate were species specific and related to the indigenous environment of a species.
Plants in the interiorscape have many documented benefits, but their potential for use in conjunction with mechanical heating, ventilation, and air conditioning (HVAC) systems to humidify dry indoor environments requires more study. In this research, evaporation and evapotranspiration rates for a root medium control, variegated spider plants (Chlorophytum comosum), and green jade plants (Crassula argentea) were measured over 24 hours at 25% and 60% relative humidity (RH) and 20 °C to generate data for calculation of the leaf surface area and number of plants necessary to influence indoor humidity levels. Evaporation and evapotranspiration rates were higher for all cases at 25% RH compared with 60% RH. At 25% RH during lighted periods, evapotranspiration rates were ≈15 g·h−1 for spider plants and 8 g·h−1 for jade plants. Spider plants transpired during lighted periods due to their C3 photosynthetic pathway, whereas jade plants had greater evapotranspiration rates during dark periods—about 11 g·h−1—due to their crassulacean acid metabolism (CAM) photosynthetic pathway. A combination of plants with different photosynthetic pathways (i.e., C3 and CAM combination) could contribute to greater consistency between evapotranspiration rates from day to night for humidification of interior spaces. Using the measured data, calculations indicated that 32,300 cm2 total spider plant leaf surface area, which is 25 spider plants in 4-inch-diameter pots or fewer, larger plants, could increase the humidity of an interior bedroom from 20% RH to a more comfortable 30% RH under bright interior light conditions.
Abstract
Daily watering gave increased growth of jade plants over weekly watering if fertilizer was applied. The optimum fertilizer rate with either weekly or daily watering was calculated as 100 ml of 250 ppm N of a 20N:8.6 P:16.6K fertilizer per 10 cm pot.
CO2 assimilation rate of Crassula hybrid `Himaturi', a succulent ornamental species with the crassulacean acid metabolism (CAM) photosynthetic pathway, was affected by light intensity (50, 100, 300 μmol·m–2·s–1), photoperiod (16/8, 8/16 h day/night), and temperature (30/25, 25/20 °C day/night). Maximum assimilation of CO2 occurred at 300 μmol·m–2·s–1 of diurnal irradiance, 16/8 h day/night photoperiod, and a day/night temperature of 30/25 °C. Diurnal CO2 assimilation patterns of nine succulent ornamental CAM species were evaluated (300 μmol·m–2 s–1, 35/25 °C day/night and a 16/8-h day/night photoperiod) for CO2 fixation. Of the nine ornamentals, Crassula `Himaturi' had the highest and Echeveria derembergii the lowest maximum CO2 absorption rate (13.0 vs 2.4 μmol kg–1·s–1), total nighttime (179.3 vs 13.4 mmol·kg–1), and 24 h total (200.6 vs 19.0 mmol·kg–1) absorption. Based on the CO2 assimilation patterns, the nine ornamentals were separated into two groups: 1) full CAM (Faucaria tigrina, Gasteria gracilis var. minima, Haworthia cymbiformis, and Haworthia fasciata); and 2) weakly CAM (Adromischus clarifolius, Crassula hybrids `Moonglow' and `Himaturi', E. derembergii, and Haworthia retusa).
Comparison of pinching methods on selected species of Columnea, Kalanchoe , and Crassula HortScience 22 72 74 Meijón, M. RodrÃguez, R. Cañal, M.J. Feito, I. 2009 Improvement of compactness and floral quality in azalea by means of application
increase ornamental value of succulent plants. Metal halide and high-pressure sodium lamps changed the leaf color of Crassula ovata (‘Hummel’s Sunset’ and ‘Gollum’ varieties) ( Park et al., 2015 ). The most desirable leaf color, red, was obtained under
Comparison of pinching methods on selected species of Columnea, Kalanchoe and Crassula HortScience 22 72 74 Mikkelsen, J.C. 1987 Commercial aspect of new crop development Acta Hort. 205 49 56 Nightingale, A.E. 1970 The influence of succinamic acid 2
on selected species of Columnea, Kalanchoe , and Crassula HortScience 22 72 74 McMahon, M.J. Kofranek, A.M. Rubatzky, V.E. 2007 Hartmann's plant science: Growth, development and utilization of