Variation of ¹⁴C assimilate export and partitioning in reduced progressive senescent and senescent sorghums [Sorghum bicolor (L.) Moench] and the potential use of anatomical features as a genetic marker for variation in sorghum /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1992.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | Research was undertaken to identify variations in 14C-assimilate export from leaves, partitioning patterns, non-structural carbohydrate concentrations, and anatomical differences in sorghum. Two reduced progressive senescent (RPSC), RTx430 and B.35, and two senescent (SC) sorghums, BTx378 and RTx7000, were field grown at College Station, Texas in 1989 and 1990. The first fully expanded leaf at panicle differentiation and the penultimate leaf at anthesis and grain filling was exposed to 3.7 MBq of 14CO2 for six min while sealed in an illuminated leaf chamber at a constant temperature of 30°C. Ten disks were punched from the leaf to quantify and analyze export. Four days after exposure, whole plants were collected for agronomic, histological, non-structural carbohydrate, and partitioning studies. No differences in agronomic harvest data between RPSC and SC sorghums were detected. Midge (Contarinia sorghicola) damage reduced grain yields of RTx430 and B.35 in both years. Histological results showed that RTx430 had significantly smaller distances between minor vascular bundles and significantly smaller minor bundle phloem areas than the other cultivars under study. Yield and phloem area were found to be negatively correlated. Specific radioactivity and concentrations of sucrose within the leaf punches of B.35 were greater than RTx430, RTx7000, and BTx378 at all growth stages. Partitioning data supported the conclusions that B.35 retained higher levels of 14C-assimilate and sugars within leaf punches and the leaf exposed to 14CO2. Partitioning data within labeled leaves showed that sucrose concentrations increased gradually within labeled leaves of B.35, BTx378, and RTx7000 over growth stages, but were unchanged for RTx430 at the different growth stages. Stem sucrose concentrations of B.35 were significantly greater than all other cultivars over all growth stages. Variation in 14C-assimilate export, partitioning patterns, and non-structural carbohydrate concentrations was most pronounced within the two RPSC sorghums involved in this study. Reduced progressive senescence within sorghum and the stay green characteristic that have been associated with B.35 are two different physiological phenomenons and should not be used interchangeably. Leaf export, whole plant partitioning, and histological data suggests physiological and anatomical characteristics of RTx430 and B.35 differ. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Plant Breeding." |
| Physical Description: | xxii, 183 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |