Crown gall disease of nursery stock

"Crown gall is a bacterial disease that affects many species in more than 40 plant families. It occurs commonly on young nursery stock including willow, poplar and other shade trees, nut-bearing trees, pome fruits and stone fruits."--First page.Einar W. Palm and Anton Novacky (Department of Plant Pathology, College of Agriculture)Revised 5/85/5

Alterations of transmembrane potentials after mechanical-stress and aging

Meeting abstrac

Nematode induced giant cells - A model system for membrane potential measurements

No abstract availabl

Transmembrane potentials of parenchyma cells and nematode-induced transfer cells

A comparison of transmembrane potential (pd) properties of parenchyma cells and giant transfer cells induced by a root-knot nematode in the roots ofImpatiens balsamina has been made. Apart from some differences in rate of response to a few treatments, parenchyma and giant cells had similar pd values; active and passive components of the pd (cyanide, azide); responses to total ion concentration, pH and potassium concentration; responses to protein synthesis inhibitors (puromycin, cycloheximide and actinomycin D) and responses to sugars. Both parenchyma cells and giant cells are depolarized by puromycin, cycloheximide and actinomycin D. The cells recover from the depolarization in the presence of cycloheximide, suggesting that this presumed protein synthesis inhibitor does not act in a straight-forward manner. The cells do not recover in the presence of puromycin or actinomycin D. Parenchyma cells and giant cells clearly have different metabolic rates and ion fluxes, but their pd responses are the same. This suggests that the pd does not reflect metabolic activity or ion fluxes of a cell, but is strictly controlled in itself. Part of this control may be via a feedback mechanism acting on an electrogenic pump. The depolarization caused by glucose is induced by aging the cells after excision. The effect is discussed in terms of an H+ dependent cotransport system and an ATPase permease system. The apparent normality of pd responses of nematode-induced giant transfer cells suggests that they may be a useful model system for experiments on higher plant cells