Study On Physiological Characteristics And Genetic Mapping Of A Spotted-leaf Wheat Mutant LF2010

In this research a spotted-leaf wheat mutant LF2010which was obtained from ananther culture line H261that mutated with EMS was chosen as material，andmorphological characteristics, chloroplast ultrastructure, physiological characteristics,inherited model and Genetic mapping were studied. The main research findings wereas follows:1. Morphological characteristics: The spot was induced both by light andtemperature. With natural light conditions and when environment temperature isabove8℃, then the yellow spots appeared on wheat leaves. The phenotype expressedon three-leaf stage, accompanying with the whole growth period. The trypan bluestaining showed that there were no dead cells at the spot position.Influence on agronomic characters: The1000-grain weight and flag leaf widthof the mutant had no significant difference with those of the wild type but most ofagronomic characters such as the grain weight per plant, plant height, spike length,grain number per spike, spike number per plant, seed setting rate, and flag leaf lengthwere lower than the wild type.2. Chloroplast ultrastructure observation showed that chloroplast at the yellowposition clearly lacked developed thylakoid membranes and grana stacks, but insteadcontained plastoglobule structures. There were different chloroplast variation of thegreen position: few chloroplasts were normal however most of the chloroplasts weredifferent in the ultrastructure, some chloroplasts were spherical, the number ofgranum-thylakoids and grana lamellae became fewer, even some chloroplasts’membrane were completely disappeared.3. The chlorophyll and corticoid contents of LF2010were measured in differentstages. The content of chlorophyll a and chlorophyll b had no significant differencewith the wild type before spots appeared on the leaves, but after the symptomappeared on the leaves the mutant plants differed from normal plants. However, the corticoid content of LF2010had no difference with the wild type after the symptomappeared on the leaf, only when the spot number is large on the leaf the corticoidcontent of LF2010was lower than normal plants. To sum up, spots mainly affectedthe metabolic balance. Like chlorophyll, the photosynthetic characteristics had nosignificant change before spots appeared, but after the symptom appeared on theleaves, the mutant’s lacking of photosynthetic assimilation led to lower photosyntheticrate.4. Genetic analyses based on F1, F2, and BC1populations revealed that the traitwas controlled by a recessive gene, located on5AL of wheat chromosome,13.5cMaway from marker Xwmc388and42.4cM away from cfa2187.