Paper Session I-C - Seeds II: More Tomatoes from Space

NASA Life Sciences Outreach, in collaboration with several other organizations, is getting ready to release space exposed seeds to teachers and students. This project, called Space Exposed Experiment Developed for Students II (SEEDS II) was designed to provide teachers and students with seeds and information so that they can conduct biological research relating to the effects of the space and undersea environments

GEL--a computer tool for DNA sequencing projects.

The GEL program for entry and analysis of DNA sequencing information is discussed, and examples of interaction with the program are presented. The current version of the program represents the last of several revisions to the first GEL program, reported previously in this journal (1). Improvements and additions have been made, making the current GEL a particularly useful laboratory tool for molecular biologists engaged in DNA sequencing projects

Toxicidade da mistura formulada de imazethapyr e imazapic sobre o azevém em função do teor de umidade do solo Injury caused by the formulated mixture of the herbicide imazethapyr and imazapic in raygrass as affected by soil moisture

Herbicidas do grupo das imidazolinonas têm, em geral, fraca adsorção ao solo e alta solubilidade em água, e, por isso, os níveis de umidade do solo podem alterar a disponibilidade desses herbicidas e seu efeito sobre culturas suscetíveis. Com o objetivo de comparar o efeito de doses da mistura formulada de imazethapyr + imazapic (75 + 25 g i.a. L-1) sobre plantas de azevém, cultivadas em solo com três níveis de umidade, foi realizado um experimento em casa de vegetação, no delineamento em blocos ao acaso com quatro repetições. Os tratamentos foram constituídos pela combinação de sete níveis do fator dose (0, 100, 200, 300, 400, 600 e 800 mL ha-1 do produto formulado), combinados com três níveis do fator umidade do solo (0, -10 e -100 kPa). Houve aumento na toxicidade e na taxa de redução da massa da matéria seca das plantas com o aumento nas doses do herbicida, sendo esses efeitos menores em solo com teor de água de -100 kPa. O teor de água no solo altera a toxicidade da mistura formulada de imazethapyr + imazapic sobre o azevém, sendo a cultura mais afetada em solos com maiores níveis de umidade.<br>The imidazolinone herbicides have, in general, low soil sorption and high water solubility, and for this reason, the levels of soil moisture can affect the availability of these herbicides and their effect on susceptible crops. Aiming at comparing the effect of rates of the formulated mixture of imazethapyr + imazapic (75 + 25 g a.i. L-1) on the growth of ryegrass plants in soil with three levels of moisture, an experiment was performed in greenhouse, in a randomized block design with four replications. The treatments were a combination of seven levels of the factor rate (0, 100, 200, 300, 400, 600 and 800 mL ha-1 of formulated product) combined with three levels of soil moisture factor (0, -10 and -100 kPa). There was an increase in injury and reduction of shoot dry weight with increasing rates of the herbicide, with lower effects in soil with -100 kPa moisture content. The water content in soil alters the injury caused by the formulated mixture imazethapyr + imazapic on ryegrass, with this crop being the most affected in soils with higher moisture levels