Photocontrol of spore germination and elementary processes of development in fern gametophytes

Abstract

SynopsisSpore germination and the subsequent processes of development in fern gametophytes such as the induction, swelling and phototropism and protonemal growth and the progression of component phases in the cell cycle are antagonistically regulated by phytochrome and chemically unknown, blue and near-ultraviolet light-absorbing pigment(s). The physiological capacity to adjust these developmental processes to the seasonal and other environmental changes by wavelength, timing and direction of irradiations with near-ultraviolet, visible and far-red lights and also the electric vector of polarised light, is crucial for fern development. The diversity of Pfr requirement and of recovery time from blue light-induced inhibition in a spore population results in variations in the timing of spore germination, so that wild fern species may find a chance for survival under natural conditions. Photocontrolled processes are differentiated temporally and spatially in the course of fern morphogenesis, especially in the haploid generation. Using this material, the premitotic positioning of the nucleus and protein synthesis were studied.