Search Results
Abstract
Activated carbon stimulated seed germination of lettuce (Lactuca sativa L.) in soil and vermiculite. Stimulation was strongly dependent upon the moisture potential. Germinating seeds were shown to excrete an inhibitor into the micro-environment which cannot diffuse away rapidly at moisture potentials near the soil field capacity or at analogous potentials in vermiculite. Increasing the moisture potential or adding activated carbon caused rapid removal of inhibitor from the seed micro-environment.
Abstract
The rate and total germination of cucumber (Cucumis sativus L.) seeds incubated at 12°C was markedly increased by acetone infusion with fusicoccin (FC). Gibberellic acid (GA4/7) was less effective than FC but more effective than GA3 or (2-chloroethyl)phosphoric acid (ethe-phon) in promoting rapid germination. Infusion of GA4/7 alone or in combination with kinetin and/or ethephon into muskmelon (Cucumis melo L.) seeds increased total germination at 16°C The growth regulators were generally not effective in promoting low temperature germination of watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) seeds.
Abstract
The rate and total emergence of lettuce (Lactuca sativa L. ‘Empire’) seedlings incubated at 33°C for 10 hr, alternating with 23° for 14 hr, was markedly increased by seed treatment with 0.5 mM fusicoccin (FC). Neither gibberellic acid (GA) nor kinetin (K) were effective in improving emergence when used alone. The combination of FC with GA or K appeared to give a synergistic enhancement of emergence rate. The radicle elongation of seedlings was reduced by seed treatment with FC, K, or combinations of FC, GA, and K in tests at 20°. The greatest reductions were caused by combinations that included FC. The inhibiting effect of FC on radicle growth was reduced by using a concentration of 0.05 mm. Treatment with 0.05 mm FC resulted in slower emergence but gave the same total emergence as 0.5 mm FC at high temperature. Both FC and GA stimulated hypocotyl elongation.
Abstract
Leaves from ‘Washington’ navel and ‘Valencia’ oranges, ‘Dancy’ and ‘Kinnow’ mandarins and ‘Marsh’ grapefruit were analyzed for 5 years. Significant differences between cultivars were found for N, P, K, Ca, Mg and Fe levels but not for Zn, Cu and Mn. Concentrations of the potentially toxic elements, Na, Cl, B, and Li, were significantly different at low non-toxic levels. Lowest values occurred in oranges and highest in ‘Kinnow’ mandarin and ‘Marsh’ grapefruit. Compared with rough lemon, sour orange rootstock decreased N in ‘Valencia’, increased K in ‘Kinnow’ and increased Ca and decreased Mn, Na, B and Li in all cultivars. There were wide annual variations in N, K, P, Ca, Mg, Zn, Mn and Cu levels in all cultivars.
Abstract
(2-chlorethyl)trimethylammonium Chloride (chlormequat) sprayed on tipped Clusters of girdled ‘Cardinal’ grape (Vitis vinifera L.) at 250 to 1000 ppm during bloom increased the number of seeded berries per Cluster but reduced berry weight Heavy Cluster thinning increased berry weight on chlormequat treated Clusters. Succinic acid-2,2-dimethylhydrazide (SADH) did not increase seeded berry set or affect any of the other fruit characteristics measured at the concentrations tested. The synthetic cytokinin, 6-(benzylamino)-9-(2-tetrahydropyranyl)-9H purine (PBA), resulted in a marked increase in seeded berries at 300 ppm, but the number of shot-berries was also increased.
Abstract
In 1967, 10 ppm of gibberellic acid (GA) applied to ‘Thompson Seedless’ grape inflorescences 10 days before bloom reduced the set of normal berries by 20%. In 1968, either 10 or 30 ppm GA applied 10 days before bloom reduced berry set by 8.2% and similar treatments applied at the beginning of bloom (< 1% of calyptras had fallen) reduced berry set by 21%. GA applied at 50% or 70% bloom was ineffective as a thinning agent and increased shot-berries in proportion to concentration. Direct counts of berries set relative to number of flowers present are necessary to estimate fruit thinning responses.