Effects of extracts of Alnus glutinosa seeds on growth of Frankia strain ArI3 under static and fermentor culture conditions |
| |
Authors: | Einar Ringø Einar Clausen Erik Løvaas Marijke Van Ghelue Bjørn Solheim |
| |
Institution: | (1) IFAS, Citrus Research and Education Center, University of Florida, 700 Experiment Station Road, 33850 Lake Alfred, FL, USA;(2) Present address: W.K. Kellogg Biological Station, Michigan State University, 3700 E. Gull Lake Dr., 49060 Hickory Corners, MI, USA;(3) Present address: Department of Horticulture, The Pennsylvania State University, 16802 University Park, PA, USA |
| |
Abstract: | The amount of root mortality caused by root pathogens such as Phytophthora nicotianae (syn. Phytophthora parasitica) has typically been inferred from the net change in root length density in sequential soil cores. Because such measurements
give information only on net changes in root populations, the actual rate of root turnover is often underestimated. We used
minirhizotrons to track the fate of a large number of individual fine roots of mature field-grown citrus trees over a 6-month
period. This method enabled us to examine the effect of P. nicotianae population levels on fine-root mortality. Seasonal and genotypic variation in patterns of citrus fine root mortality were
associated with variation in population levels of P. nicotianae. Fine root lifespans were shorter when populations of P. nicotianae were high. Fine roots of the Phytophthora-susceptible rootstock, rough lemon (Citrus jamibhiri), had shorter median lifespans and supported larger populations of P. nicotianae than the fine roots of the more tolerant rootstock, Volkamer lemon (Citrus volkameriana). Rates of root mortality were either relatively constant for roots of all ages, or increased with age; the latter pattern
was most pronounced for Volkamer lemon roots. Differences in the age-dependence of root mortality may, therefore, play a role
in genotypic differences in tolerance of Phytophthora root rot by these two rootstocks. H Lambers Section editor |
| |
Keywords: | Citrus jambhiri Citrus volkameriana minirhizotron Phytophthora nicotianae root demography |
本文献已被 SpringerLink 等数据库收录! |
|