Morphometric characteristics of bacteroidal tissue in yellow lupine (Lupinus luteus L.) nodules

Morphometric methods were used to analyse the bacteroidal tissue in yellow lupine nodules. Volume fraction - Vv, surface area - Sv and ratio of surface area to its volume - R, were calculated from electron micrographs for some selected cell structures in 9, 13, 15, 20, 29 and 60 day-old nodules. The rate at which bacteroid Vv increased varied in time. Between days 13 and 20 of nodule development, bacteroid Vv increased in geometrical progression. Rough endoplasmic reticulum was active in nodule development and/or protein manufacturing necessary for the functioning of the system whereas the role of mitochondria was apparently limited.