Mary E. Dale
Mary E. Dale
International plant germplasm resources are an invaluable source of information, and bringing viable plant materials into the United States is a necessity for many researchers.
Quarantine regulations vary based on the plant pests and pathogens occurring in the country of origin to prevent the introduction of injurious plant pests and diseases. These regulations also depend on the type of germplasm (such as live plant, cuttings, or seeds), size and age of specimen, and the media grown in. Plants in soil are prohibited, while those in agar, or bare root may be allowed to enter.
Procedures to follow for bringing plant germplasm of international origin (including CITES species), forms and permits, ports of entry, delays to expect or avoid along with other information on successfully bringing plant germplasm resources into the United States will be discussed.
Mary E. Dale, Ellen T. Paparozzi and James D. Carr
Cuttings of Euphorbia pulcherrima Willd. ex Klotzsch `Dark Red Annette Hegg' were grown hydroponically in minus S Hoagland's solution modified to supply 0, 1, 2, 4, or 8 mg S/liter for 8 weeks. Nutrient solution changes; visual observations, sampling of tissue, and measurement of electrical conductivity and pH were done every 2 weeks. Deficiency symptoms appeared after 4 weeks of growth in treatments supplying 0 or 1 mg S/liter and occasionally in treatments supplying 2 mg S/liter. Symptoms included reddening of the petiole and main vein of new leaves followed by yellowing of these leaves. Leaf tissue S levels ranged from 700 to 3600 mg S/kg of plant. Deficient levels were identified as <2200 mg S/kg of plant. Suggested critical tissue levels of S would be 2300 to 3000 mg S/kg of plant leaf tissue.