Loss of recovery capacity of plasmalemma k influx after cutting in chlorsulfuron pretreated maize roots.

Active K(+) influx was studied in apical segments from maize (Zea mays L., hybrid lines XL 342) and pea (Pisum sativum L. var Laxton superbo) seedlings pretreated with the herbicide chlorsulfuron (2-chloro-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl) aminocarbonyl]benzenesulfonamide).Even though both plants were sensitive to chlorsulfuron, a strong inhibition of K(+) uptake only was evident in maize root segments after 12 hours pretreatment with 10 micromolar chlorsulfuron. The inhibition was revealed only when maize root segments were washed for 2 hours before uptake measurements. This was done in order to recover K(+) influx inhibited by cutting injury. Consequently, we demonstrated that roots from chlorsulfuron pretreated maize seedlings lost the capacity to recover from cutting injury by washing. By contrast, K(+) influx in pea roots was not inhibited by chlorsulfuron because pea roots notoriously do not exhibit the ;washing' effect.