Sucrose uptake was studied in isolated, immature pea cotyledons (Pisum sativum L. cv Marzia) in relation to their developmental stage. During the developmental period examined the water content of the cotyledons decreased from approximately 80% "stage 1" to approximately 55% "stage 2". When assayed in an isotonic medium (400 osmoles per cubic meter) the influx capacity per gram fresh weight for...

The timing of maturation in insects is determined by reaching a critical developmental stage, at which development becomes committed to metamorphosis (e.g. Nijhout, 1981). The critical stage is a well-de®ned developmental stage, marked by a small ecdysone pulse (Berreur et al., 1979). It leads to a shift in hormonal levels, which sets the stage for further developmental changes (Riddiford, 1993...

This paper reports a model of a developmental agent. It is inspired by some characteristics of Piagets sensorimotor stage. During this stage essential skills for creative thinking are developed. Our computational model attempts to shed some light about how these abilities arise and, in this way, contribute to the study of the developmental side of computational creativity.

Objective: In recent years, antiviral drugs have been used widely in the glob to prevent and treat viral diseases. They injected into eggs to eliminate pathogens and prevent of egg transmission of disease, but the adverse effects of drugs have always been a major concern. There is little information available about the safety of antiviral drugs in the embryonated eggs of birds. The objective of...

Objective: In recent years, antiviral drugs have been used widely in the glob to prevent and treat viral diseases. They injected into eggs to eliminate pathogens and prevent of egg transmission of disease, but the adverse effects of drugs have always been a major concern. There is little information available about the safety of antiviral drugs in the embryonated eggs of birds. The objective of...

the green lacewing chrysoperla carnea (stephens) (neuroptera: chrysopidae) is one of the important natural enemies of pest insects. present study conducted to evaluate the side effects of some plant extracts, calotropis procera (willd.) r. br. (asclepiadaceae), fumaria parviflora lam. (fumariaceae), eucalyptus spp. (myrtaceae) and pesticide amitraz on biological parameters of the second instar ...

Climate change is predicted to increase sea level and cause saline intrusion of coastal freshwaters. This will have consequences for freshwater organisms inhabiting such areas; developmental phenotypic plasticity may facilitate the persistence of freshwater species under such scenarios of increased salinity. Here we investigated developmental plasticity under different salinity treatments (S = ...

The rice resistance gene Xa21 confers resistance against the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo). The molecular genetic mechanism controlling the integration of the Xa21-mediated disease resistance response with the developmental program in rice is under study in this model system. Reproducible means of infecting plants at certain developmental stages were designed based on t...