A large number of morphological effects have been obtained from induced polyploidization. However, one of the immediate effects of polyploidy is an increase in cell size due to the increase in nuclear content which causes a reduction in a cell division during their growth and development. This “gigas effect” is mostly observed in different plant organs of commercial interests such as leaves, seeds and flowers
[19]. Doubling through colchicine caused an increase in number of leaves, number of branches, plant height and stem length in salvia (
Salvia coccinea cv Coral Nymph)
[20], jasmine tobacco (
Nicotiana alata)
[21], selfheal (
Prunella vulgaris)
[22], lily (
Lilium)
[23], chaste tree (
Vitex agnus castus)
[5], orchid (
Dendrobium nobile)
[24], ornamental ginger
[25], crape myrtle (
Lagerstroemia indica)
[26], calendula (
Calendula officinalis)
[3], matted sea-lavender (
Limonium bellidifolium)
[27], white orchid tree (
Bauhinia acuminate)
[28] and London plane (
Planatus acerifolius)
[29]. Induced polyploidy also increased the leaf color in balsam (
Impatiens balsamina),
[30], self-heal (
Prunella vulgaris)
[22], wishbone flower (
Torenia fournieri)
[31], marigold (
Tagates erecta)
[32], chaste tree (
Vitex agnus castus)
[5] and chrysanthemum (
Dendranthema grandiflora)
[33], along with increasing their leaf area as well. Induced polyploidy produced ovate shaped leaves having obtuse base in gymnostachyum (
Gymnostachyum zeylanicum)
[34] and whorled arrangement of leaves in balloon flower (
Platycodon grandiflorus)
[35]. Highest variation in color and shape of leaves has been observed in tetraploid plants of pelargonium (
Pelargonium graveolens),
[36].
Mitotic chromosome doubling through colchicine treatment results in production of large sized inflorescence with increased floral parts in salvia (
Salvia coccinea cv. Coral Nymph), however flowering has been delayed up to 10–30 days
[20]. In chaste tree (
Vitex agnus castus), polyploid plants had larger flowers with longest posterior petals and unique colors. Tetraploid plants of feverfew (
Tanacetum parthenium) had increased flower weight and diameter but produced only up to 50% of flowering as compared to its diploid plants
[37]. Also, in ornamental wild ginger species (
Larsenianthus careyanus), chromosome doubling caused an increase in leaf number, lamina length, flower size along with length of inflorescence and spike length
[25]. Dense flowering with erect, compacted and short inflorescence was produced in gymnostachyum (
Gymnostachyum zeylanicum), from 0.04% colchicine treated plants
[34]. Tetraploidization in African violets (
Saintpaulia ionantha) produced 5% white flowers with purple margin. After 7 days of flowering, flower color pattern changed from white petals with purple border to whole purple petals and this pattern has been maintained for six successive generations
[38]. Tetraploid plants of pelargonium (
Pelargonium graveolens) cv. Black Velvet Scarlet F1 produced flowers with rough edges, where flowers of cv. Gizela produced burnt margins
[36]. Similarly, colchicine treatment produced more flowering with large stigma in jasmine tobacco (
Nicotiana alata)
[21], larger flower height with increased lip width in wishbone flower (
Torenia fournieri) [31] increased the number of petals in garden balsam (
Impatiens balsamina)
[30] and increased flower diameter up to 1.2–1.3 folds in tetraploid plants of matted sea-lavender (
Limonium bellidifolium) as compared to its diploid plants
[27]. Colchi-tetraploids of chrysanthemum (
Chrysanthemum carinatum) had larger flowers with thicker petals that helped to improve their vase life
[39]. Also, in gladiolus, colchicine induced putative polyploids had larger flower size with maximum vase life. Moreover, novel variation in flower morphology like serrated margins with ruffled edges along with pointed outgrowth has been observed in flower petals of gladiolus
[40]. Higher colchicine concentration in African marigold (
Tagetes erecta) initiated early flowering (59 days) in treated plants as compared to control plants (80 days). Also, a higher number of flowers with increased diameter and weight of flowers have been produced in polyploid plants
[41].
Apart from improving ornamental traits like flower or leaves in ornamental plants, polyploidy also increases the plants yield in the form of both sexual and asexual reproductive structures. After colchicine treatment, a significant increase in seed size and weight was observed in crape myrtle (
Lagerstroemia indica)
[26] and Madgascar periwinkle (
Catharanthus roseus)
[42]. Whereas, colchicine also increased seed number, seed weight and fruit setting percentage in balsam (
Impatiens balsamina)
[43]. Similarly, in vegetatively propagated crops like
Lilium, induced chromosome doubling produced wider bulb scale
[23], however, in orchid (
Dendrobium nobile), polyploidization decreased pseudobulb diameter up to 64.9%
[44].