Comparative assessment of morphological, cytological, and photosynthetic characteristics of the induced octoploid and its tetraploid counterpart of Celosia argentea L

Abstract

Background: Celosia argentea is a widely recognized plant for its ornamental qualities and therapeutic uses in traditional medicine. As demand for such multipurpose plants grows, enhancing its phenotypic and physiological traits could further expand its commercial potential. Polyploidization, particularly through chemical treatments like oryzalin, offers a method to induce genetic variation and potentially improve desirable traits in plants.

Results: Tetraploid (2n = 4×= 36) nodal segments of C. argentea were treated with oryzalin under in vitro conditions, resulting in successful induction of octoploidy (2n = 8×= 72). Flow cytometry and chromosome counting confirmed polyploidization, with the highest induction rate achieved using 40 µM oryzalin for 24 h. Comparative analyses between octoploid and tetraploid plants revealed significant differences in morphological traits, including increased stem and leaf thickness, larger leaf area, inflorescence characteristics and more compact growth in the octoploids. Additionally, octoploids exhibited enhanced chlorophyll content and altered photosynthetic characteristics, along with notable changes in stomatal size and density. Ploidy stability was maintained across generations, ensuring the heritability of the induced traits.

Conclusions: In vitro polyploidization in C. argentea led to significant phenotypic and physiological improvements, demonstrating its potential for application in ornamental horticulture and plant breeding. This research contributes to the understanding of the impact of in vitro polyploidization on plant development, offering insights for the commercial cultivation and enhancement of C. argentea.

Clinical trial number: Not applicable.

Keywords: Chromosome doubling; Cockscomb; Crop improvement; Offspring stability; Oryzalin; Polyploid induction; Polyploidization.

Fig. 1

Morphological trait comparison between tetraploid and induced octoploid plants of Celosia argentea. Traits assessed include (A) shoot length, (B) number of nodes per shoot, (C) internodal distance, (D) leaf area, (E) leaf thickness, and (F) stem thickness. Different letters on the vertical bars indicate statistically significant differences between tetraploid and octoploid plants (Student’s t-test, p < 0.05) (n = 20)

Fig. 2

Phenotypic characteristic of (A) tetraploid (on left) and the (B) octoploid (on right) plant of C. argentea

Fig. 3

Leaf characteristics comparison between (A) tetraploid and (B) induced octoploid plants of C. argentea

Fig. 4

Floral inflorescence characteristics comparison between tetraploid and induced octoploid plants of Celosia argentea. Traits include (A) number of inflorescences per shoot, (B) inflorescence length, (C) inflorescence width. Different letters on the vertical bars indicate statistically significant differences between tetraploid and octoploid plants (Student’s t-test, p < 0.05) (n = 20)

Fig. 5

Floral inflorescence features of (A) tetraploid and (B) induced octoploid plants of C.argentea

Fig. 6

Seed morphology and size of (A) tetraploid and (B) induced octoploid plants of C.argentea

Fig. 7

Seed characteristics comparison between tetraploid and induced octoploid plants of Celosia argentea. Traits include (A) number of seeds per inflorescence head, (B) seed size, (C) seed weight, and (D) seed germination rate (%). Different letters on the vertical bars indicate statistically significant differences between tetraploid and octoploid plants (Student’s t-test, p < 0.05) (n = 20)

Fig. 8

Stomatal frequecy and characteristic comparison between tetraploid (left) and induced octoploid (right) plants of C. argentea under 60× magnification. The measurement scale in the image is in “µm”

Fig. 9

Compararison of photosynthetic parameters including A) Total Chlorophyll, B) Fv/Fm, C) Pi_Abs, D) ABS/RC, E) Sm, F) SPAD, G) qP, H) NPQt and, I) LEF between tetraploid and induced octoploid plants of C. argentea. Different letters on the vertical bars indicate statistically significant differences between tetraploid and octoploid plants (Student’s t-test, p < 0.05) (n = 30)