Regulating cucumber grafting by interactions of cytokinins in xylem exudates of rootstock and basipetol polar auxin transport of scion at graft union

Abstract

Trails were made to investigate the role of cytokinin in xylem exudates of different rootstocks of cucurbitaceous plants (squash- pumpkin - Bottle gourd-Figleaf gourd) on the progress of cucumber grafting. Also basipetal polar auxin transport out of hypocotyls of previous rootstocks and cucumber scion was also determined in relation to xylem exudates cytokinin. Pregrafted rootstocks showed great variation in cytokinin concentrations. Also the concentration of basipetal polar auxin transport out of hypocotyls of previous rootstocks was greatly varied a directly proportion between the concentration of two hormones was detected. Rootstock with higher cytokinin concentration in xylem exudates had higher auxin transport out of its own hypocotyls and vice versa was true. After grafting processes basipetal auxin transport through out grafting union could be used as indicator for grafting success. So the higher the auxin transport was the most successful grafting. Furthermore, cytokinin levels in xylem exudates 1 cm above the grafting union could be also used as second indicator for grafting success. The cytokinin in xylem exudates of rootstocks and basipetal polar auxin transport out of cucumber scion as hormonal signaling in rootstock-scion interactions was discussed. © 2010, INSInet Publication.