Efeito do tempo de inoculação e de estocagem na penetração e migração de juvenis de segundo estádio de Meloidogyne javanica e Heterodera glycines em soja

Abstract

To study the penetration and migration of Meloidogyne javanica and Heterodera glycines were defined on soybean young roots cultivar Embrapa DOKO two regions characterized as: region 1- from root cap to the initial of vessel bundles-visualization including, then, the root cap, meristem and forming- new tissues, region 2- from the initial vessel bundles on. On these regions, the second stage juveniles (J2) numbers were assessed after various inoculation time periods and from J2 stored in water. The inoculation times affected, quantitatively, the M. javanica J2 number on regions 1 and 2 of soybean roots. Initially (24 h after inoculation) the M. Javanica J2s agglutinated in regon1,while J2 number decreased on region 1, it increased on region 2 with J2 moving 6 mm in 3 days between the vascular bundles. Then, become evident that the M. javanica J2 penetrated throngh roots cap. Unlikely, H. glycines J2 was not found in region 1, and the J2 number in region 2 decreased with inoculation time. However, the majority of H. glycines J2 was found at 20 mm from the root cap on the side of epidermal ruptures, possibly, the J2 penetration site, from where it moved directly to central cylinder. The M. javanica J2 storage time of 8 days reduced the total J2 number and those found in region 2, but the distance that J2 moved in 4 days was not altered. However, all storage periods tested, reduced, drastically, the H. glycines J2 found in region 2. Then, the penetration sites, J2 migration and the J2 storage effects are differentials in infested soyean by M.javanica and H. glycines.