. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 60 J. M. HUSH AND R. L. OVERALL. CURRENT IN CURRENT OUT WOUND B The effect of wounding the pea root 3 mm back from the tip: current patterns around the wound site (A) 2 min after wounding (mean ± ' <» h after wounding (mean ± SEM of 7 roots): (C) 6 i . n ± SEM of 6 roots); (D) 23 h after wounding (mean oots). Diagrammatic representation of the roots as viewed fr. rents are found exclusive ;hc wound area, a dis- tinct peak of ^A servable over the wound. Five minutes after wounding ;-splays a dis- tinct asymmetry in
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 60 J. M. HUSH AND R. L. OVERALL. CURRENT IN CURRENT OUT WOUND B The effect of wounding the pea root 3 mm back from the tip: current patterns around the wound site (A) 2 min after wounding (mean ± ' <» h after wounding (mean ± SEM of 7 roots): (C) 6 i . n ± SEM of 6 roots); (D) 23 h after wounding (mean oots). Diagrammatic representation of the roots as viewed fr. rents are found exclusive ;hc wound area, a dis- tinct peak of ^A servable over the wound. Five minutes after wounding ;-splays a dis- tinct asymmetry in the pattern scellular ion cur- rents (Fig. 5a). This persists at the wound site even after 1 h (Fig. 5b), although partial symmetry is restored around the rest of the root tip by this time. Ionic composition oj the wound current Table I shows that there is no apparent effect on the wound current, of altering the levels of Na+, K+, Cl~, or H+ in the bathing medium. A very slight wound current enhancement appears to result from reducing external K+ or H+ levels, or increasing Cl~ concentration. How- ever, lowering external Ca2+ (via 1CT4 MEGTA) dramat- ically reduced the current (by about 40%) as did reason- able concentrations of two Ca:+ ion analogues and chan- nel blockers: 100 nAl La3+ cut the current by 50% (Fig. 6) and 50 ^/Gd3+ by about 30%. These results strongly suggest that a Ca2+ current or Ca2+-controlled current may be involved in the wound response. The effects of verapamil, a different type of calcium channel antago- nist, were slight; it is possible that only concentrations higher than the micromolar range employed here, would be effective. Extracellular pH Wounded roots placed on agar plates containing bro- mocresol purple caused a strong pH shift in the agar di- rectly around the wound, as indicated by the appearance of a strong purple band in the agar within a few minutes, which is focussed at the wound site (Fig. 7a). By 20 min the alkaline region is more
Size: 1077px × 2320px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
