Effects of Leaf Age and Exogenous Hormones on Callus Initiation, Rooting Formation, Bud Germination, and Plantlet Formation in Chinese Fir Leaf Cuttings

Abstract

To guide the cultivation of superior Chinese fir plantlets, we designed an L16(4)4 orthogonal experiment to determine how leaf age and exogenous hormones influence key growth processes in leaf cuttings. Hormone concentration and treatment duration significantly affected leaf cuttings in all three age categories; 6-benzylaminopurine (6-BA), 1-naphthaleneacetic acid (NAA), and treatment time exerted the strongest effects on callus initiation rates. Additionally, NAA had the largest effect on the rooting rate across all cuttings, and all three hormones significantly influenced the bud germination rate. Based on our experimental results, expected optimal treatments for callus initiation were 10 mg∙L−1 indole-3-butyric acid (IBA) for 10 min, 30 mg∙L−1 NAA for 15 min, and 10 mg∙L−1 NAA plus 30 mg∙L−1 IBA for 10 min. For the rooting rate, the expected optimal treatment was 50 mg∙L−1 NAA and 40 mg∙L−1 IBA for 5–20 min. Finally, for bud germination, optimal treatments were 20 min of immersion in water, 30 mg∙L−1 6-BA plus 50 mg∙L−1 NAA for 15 min, and 30 mg∙L−1 6-BA for 5 min. Plantlet formation only occurred in the <one-year-old leaves, and at very low rates (maximum 5.8%); this outcome is likely attributable to the mother plant’s relatively old age (five years). Plantlet formation from cuttings is dependent on ensuring the rooting rate after callus initiation. Therefore, to promote rooting rates and bud germination, we recommend leaving more xylem at the base of leaf cuttings.

Propagação vegetativa por miniestaquia de Mimosa Tenuiflora (Mart.) Benth

“…Da mesma forma, o inchamento da base foi observado em algumas miniestacas aos cinco dias e a formação de calos no mesmo período. Calos são um aglomerado de células indiferenciadas que podem desempenhar a função de curar uma determinada lesão na planta e, dependendo da densidade, podem ser indicativos de que o propágulo tem competência para produzir raízes adventícias (Zhou et al, 2018). A formação do calo também é diretamente afetada pelo tempo de imersão em auxina, tipo de corte e idade do propágulo, em que há um aumento na formação de calos, à medida que aumenta a idade cronológica, ontogenética e fisiológica do propágulo (Pimentel et al, 2019).…”

VEGETATIVE RESCUE OF Azadirachta indica BY CUTTINGS

“…One of these processes is the base swelling followed by callogenesis. Calluses are a cluster of non-diff erentiating cells that can perform a healing function of a particular wound on the plant and, depending on the density, may be indicative that the propagule has the competence to produce adventitious roots (Zhou et al, 2018). Callus formation is also directly aff ected by the time of immersion in auxin, type of cut, and propagule age, in which there is a tendency to increase callus formation as age increases (Pimentel et al, 2019).…”

Rooting Induction of a Mature Pterocarpus indicus Willd. Using Stem Cuttings Derived from Stump Epicormic Shoots

“…Similar results have also been reported from previous studies on the effect of IBA and cutting position on rooting and callusing in various trees (Benabise 2013), it does not always true in other species. For instance, callusing has been found to negatively affect the rooting of lanceolata since hormone application promotes extensive callusing that seemingly preventing the rooting, especially when used cutting from a mature donor plant (Zhou et al 2018). This implies that optimization or perhaps low concentrations of exogenous auxins should be applied, especially when using mature cuttings.…”