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  • Author or Editor: W. H. Carlson x
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Abstract

Spraying chrysanthemums at pinching with N6 benzyladenine (BA) 400 ppm and 6-benzylamino)-9-(2-tetrahydropyranyl)-9H-purine (PBA) 200 ppm significantly increased branching, while other chemicals and lower BA concn less consistently stimulated larger numbers of branches than untreated plants. The chemicals inhibited stem elongation, but only BA caused a significantly shorter stem. Ethephon delayed flowering 10 or more days for all cultivars, and BA (400 ppm) spray of stock plants prevented or delayed rooting of cuttings taken 0 to 4 weeks after treatment. Sprays of BA, PBA and ethephon applied at pinching improved branching more than treatment 2 weeks before or 2 weeks after pinching.

Open Access

Abstract

Foliar sprays of (2-chloroethyl)phosphonic acid (ethephon), 6-benzylamino purine (BA), and 6-(benzylamino)-9-(2-tetrahydropyran-yl)-9H-purine (PBA) significantly increased me branching of pinched ‘Dark Red Irene’ geranium (Pelargonium hortorum Bailey). Spraying pinched plants with 2,3,5-triiodobenzoic acid (TIBA) and indoleacetic acid (IAA) frequently increased the branch no. over pinched but untreated plants. Maximum stimulation of branching of pinched plants occurred from growth regulator sprays at the time of pinching. Ethephon and BA sprays significantly delayed flowering.

Open Access

Abstract

A temperature of 10°C resulted in the greatest synthesis of anthocyanins in foliage of marigold (Tagetespatula L.) regardless of whether cold was applied during the day or night. Response surface techniques were used to determine combinations of light and temperature which result in equal levels of anthocyanin or chlorophyll. Predicted responses indicate that as night temperature increased from 10 to 26°C, a wide range of quantum flux densities and day temperatures resulted in low anthocyanin content. Night temperature of 10° and high day temperature resulted in the same chlorophyll content as 26° night temperature and low day temperature if quantum flux density was low. No significant correlation was found between anthocyanin level and foliar phosophorus or potassium.

Open Access

Abstract

Root promotion and root inhibition were measured for geranium and poinsettia cuttings during and after treatment at medium temp of 5 to 35°C at 5°C increments for 1 to 5 days. Optimum root initiation and elongation temp from 1 day of treatment were 15 to 30°C with reduced root initiation after 5 and 35°C and inhibition of root elongation after 5, 10 and 35°C treatments. Medium treatments for 3 or 5 days at 25 and 30°C increased root initiation and elongation which continued at accelerated rates during a 5 day period following treatment. Medium temp 5, 10, 15, and 35°C for 3 or 5 days reduced root initiation and elongation during treatment, and inhibition continued after treatments of 5, 10, and 35°C. Roots became brown for both species during 35°C treatment, while roots at 25°C and below remained white. After treatment root tip vascular and cortical cells varied in size but were anatomically similar. Distances from the root tips to the 1st xylem element were largest at 25°C allowing more cortical cells in the meristematic region.

Open Access

Abstract

Four greenhouse rose cultivars were grown under 9, 12, and 16-hr daylengths from September to May during 1969-70 and 1970-71. Flower production was generally increased significantly under the 16-hr daylength, particularly during January and February. At this day length, rose stems flowered again more quickly, but with the same number of nodes present as in the other treatments. The internode between the 2 uppermost 5-leaflet leaves was significantly longer on plants grown at 16 and 12 hr than the 9-hr daylengths. Flower fresh and dry wt increased as the daylengths increased from 9 to 16 hr and the percentages of blind stems were found to decrease. Rose leaf and flower petal size were unchanged by the daylength.

Open Access

Abstract

Foliar sprays of 6-(benzylamino)-9-(2-tetrahydropyranyl)-9H-purine (PBA) at 200 or 300 ppm and 6-benzylamino purine (BA) at 500 or 1000 ppm, caused the development of 90% or more of the lateral branches of ‘Annette Hegg’ and ‘Dark Red Annette Hegg’ poinsettia (Euphorbia pulcherrima Willd.) while 2 to 4 lateral branches developed from terminal stems of “Eckespoint C-l Red” near the position of the apical meristem. (2-Chloroethyl)phosphonic acid (ethephon) sprays increased lateral branch development significantly above the control treatment but less than PBA or BA while 2, 3, 5-triiodobenzoic acid (TIBA) produced only slightly more branches than the control.

Open Access

Abstract

‘Mace’ kalanchoe usually produces dense foliage with a cluster of long cymes, but under optimal growing conditions plants grow excessively tall and quality is decreased. Growth retardation of ‘Mace’ has been achieved with daminozide (2), chlormequat (Carlson, unpublished data), ethephon (3), and ancymidol (3). Of these four compounds, ancymidol was the most effective The present study was conducted to determine the effect of increasing ancymidol concn applied at specific time periods during flower inducing (short day) conditions.

Open Access

Abstract

The number of flower buds formed on plants of Schlumbergera truncata (Haw.) Moran (Thanksgiving cactus) was reduced by high water stress during flower initiation and was unaffected by night temperature (13° vs. 17°C) under short days. Application of 100 ppm benzylamino purine (BA) increased flower bud number by 40% when sprayed 2 weeks after the initiation of a short day treatment and increased phylloclade number up to 150% when applied during long day photo-periods.

Open Access

Abstract

Flowering time, dry weight, total leaf area, and vegetative height of Tagetes patula L. were predicted on the basis of day temperature, night temperature, and quantum flux density (QFD). High temperatures (30°C) decrease flowering time regardless of QFD and greatest leaf surface area was caused by high QFD. As night temperatures increased, maximum leaf area occurred at lower day temperatures than those necessary for fastest flowering time. Each response was characterized by response surface technique.

Open Access

Abstract

Hybrid geraniums (Pelargonium × hortorum Bailey) cv. Sooner Red were grown at temperatures ranging from 10–32°C and at various quantum flux densities. The time to visible bud stage (<0.5 cm diameter) was negatively correlated to quantum flux density at a given temperature. The time required from visible bud to flower stage was negatively correlated with temperature while light had no effect. Leaf thickness, number of palisade layers, and specific leaf weight were negatively correlated with temperature, and specific leaf weight was positively correlated with quantum flux density at a given temperature. Net photosynthetic rate ranged from 5–38 mg CO2 dm-2hr-1 for temperatures of 10-37° and was optimum at 20-32°. The Q10 of respiration for hybrid geranium leaves was about 2.2.

Open Access