The effect of temperature on pollen production in carnations
SummaryFor breeding carnations the supply of good pollen may be a problem. For this reason the effect of temperature on pollen production in carnations was studied.In phytotron experiments a temperature of 23°C proved to be the optimum.
An investigation into the cause of sterility in double-flowered freesia varieties and the possibility of restoring fertility
SummaryThe sterility of double-flowered freesia is caused by the abnormal structure of the flower. It proved possible, by cultivation at higher temperatures, to induce fertile single flowers in a double-flowered variety. In winter, under natural light conditions, the most favourable temperature range is 18–20°C.In this way progeny can be obtained from seed and the application of the usual breeding methods to double-flowered freesias is made possible.
Optimal Combination and Concentration of Antibiotics in Media for Isolation of Pathogenic Fungi and Nocardia asteroides
Strains of Blastomyces dermatitidis, Sporothrix schenckii, Histoplasma capsulatum, Cryptococcus neoformans, Nocardia asteroides, and Coccidioides immitis were tested for in vitro susceptibility to polymyxin, gentamicin, kanamycin, chloramphenicol, and neomycin at concentrations of 1, 2, 4, 8, and 16 μg/ml. Polymyxin was the most inhibitory and gentamicin was the least inhibitory of the five antibiotics. Two Histoplasma mycelial strains were partially inhibited by 2 and 8 μg of gentamicin per ml and showed at least a 2+ growth at the higher antibiotic concentration. Kanamycin and neomycin produced significant inhibition of N. asteroides but otherwise were noninhibitory. A combination of chloramphenicol and kanamycin, each at 16 μg/ml, and gentamicin, at 4 μg/ml, was noninhibitory to the strains tested except for N. asteroides. Chloramphenicol at 16 μg/ml was not inhibitory for N. asteroides. The results suggest that the optimal antibiotic combination to use in the isolation of fungi and higher bacteria is chloramphenicol, 16 μg/ml, and gentamicin, 4 μg/ml. Addition of sheep blood (5%) had no effect on antibiotic susceptibility of the organisms studied.