UV-effects on young seedlings of soybean: Effects in early development and long-term effects

Abstract

Young plants are the most susceptible to ultraviolet (UV) radiation, due to the large number of growing and dividing cells. Incident UV radiation to earth has increased, even at temperate latitudes. Chronic exposure to UV light, especially UV-B (290 nm-320 nm) radiation, causes damage to land plants including reduced photosynthetic capacity, biomass yield, nutritional quality of the seed, altered patterns of species competition, plant ultrastructure and pigment production, and increased incidence of disease. Hence it is important to know how exposures early in the life cycle of the plant affect the establishment of the seedling and the production of viable seed. We found that the greatest affects of UV-B occurred very early in the plant's life cycle, notably in the first week post planting. Aside from increased mortality with increasing UV energy, UV-B treated seedlings had increased deformity, decreased ability to produce viable seeds and dysregulation of phenylpropanoid synthesis, which is dependent upon phenylalanine. Responses to high energy UV-B cause noticeably different effects in different varieties of soybean. If soybean experience higher energy UV in the early stages of growth, the effects can cause heritable changes, which will in turn effect yield and impact the viability of the next generation of seed. © 2010 Springer-Verlag Berlin Heidelberg.