Off-campus UNL users: To download campus access dissertations, please use the following link to log into our proxy server with your NU ID and password. When you are done browsing please remember to return to this page and log out.
Non-UNL users: Please talk to your librarian about requesting this dissertation through interlibrary loan.
Effects of cold on proline accumulation in sorghum pollen
Abstract
Low temperatures at the flowering stage may cause male sterility and thus yield reductions in grain sorghum (Sorghum bicolor (L.) Moench). Others found free proline in anthers associated with pollen fertility and positively correlated with seed set. The objectives were to determine whether proline concentrations increased in sorghum pollen in response to low temperature, whether accumulation of proline was related to cold tolerance, whether there was variation in response among genotypes having different maturities, whether there was a relationship between seed set and proline concentrations in pollen, and to evaluate methods for pollen viability. In the initial experiments, low temperature (20/10$\sp\circ$C day/night) was imposed to several genotypes from boot stage until maturity. Proline concentrations in pollen from treated plants increased over controls. There were genotypic differences for pollen proline concentrations, and seed number was positively correlated with proline concentrations. In another experiment, percent seed set of male-sterile lines was positively correlated with pollen proline concentrations. Plants were subjected to 20/10$\sp\circ$C day/night temperatures for one week at various stages of panicle development. A reduction occurred in seed set when cold occurred at the preleptotene/leptotene stage of microsporogenesis. When cold was applied at or later than the time of emergence of the panicle, there was no effect on seed set. Translocation of proline from the leaves to the immature pollen was proposed. Earliness was a crucial factor in avoiding cold stress when sorghums were grown under field environments created by consecutive, late planting dates. Early maturing genotypes had higher proline concentrations in pollen than later maturing genotypes. Pollen proline accumulation was positively correlated with seed set when the post-flowering stage was not severely damaged by cold. When sorghums were evaluated for pollen proline concentrations in two locations and two years, higher proline content was observed during the year having cooler temperatures. In vitro pollen germination was accomplished when pollen was collected in high humidity conditions. Pollen germination was photographed with scanning electron microscope.
Subject Area
Agronomy|Botany
Recommended Citation
Lansac, Ana Rocio, "Effects of cold on proline accumulation in sorghum pollen" (1990). ETD collection for University of Nebraska-Lincoln. AAI9034279.
https://digitalcommons.unl.edu/dissertations/AAI9034279