TITLE:
Study on Petal-Sepal Mutant of Sunflower (Helianthus annuus) after Space Mutation
AUTHORS:
Hao Feng, Jun Yang, Dengfei Li
KEYWORDS:
Space Mutation, Helianthus annuus, Petal-Sepal Mutant, Sunflower, Photosynthesis
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.7 No.17,
December
16,
2016
ABSTRACT: In this paper, we studied the morphological,
histological and photosynthetic characteristics of the stably inherited
sunflower petal-sepal mutant, and it was obtained by the space
radiation-induced mutagenesis. Afterwards, we got following results: 1) The morphological
characteristics represented that the inflorescence of petal-sepal mutant maintained
the appearance and structure of capitulum, whereas no explicit tubular flower
or ligulate flower was differentiated. 2) The histological characteristics revealed
that the petal-sepal mutant only completed the inflorescence development and
the differentiation of sepal primordia and inflorescence
primordia, without entering the differentiation stage of tubular flower primordia,
ligulate flower primordia, stamen primordia or pistil primordia. 3) The photosynthetic
characteristics showed that the photosynthetic rate, transpiration and stomatal
conductance of petal-sepal mutant were relatively weaker than the control
plants. In the end, we concluded that the petal-sepal mutant of sunflower had
only inflorescence differentiation, while several mutant genes were caused by radiation-induced
mutation, which entered an infinitely recurrent development process rather than
the floral differentiation stage. We also observed a few chloroplast
structures in the paraffin section, combined with the results of photosynthetic characteristics of petal-sepal mutant, and then
we believed that the inflorescence of petal-sepal mutant was involved in
photosynthesis to accumulate energy for plant growth.