Chitosan oligosaccharide addition affects current-year shoot of post-transplant Buddhist pine (Podocarpus macrophyllus) seedlings under contrasting photoperiods

Abstract

(2) Chitosan oligosaccharides (COS) have been used as modifiers to promote growth and mineral nutrient utilization in crop plants, but its over-year effect on current-year shoot (CYS) of juvenile trees is still unclear. In this study, Buddhist pine (Podocarpus macrophyllus) seedlings were cultured under natural and extended photoperiods with or without COS addition for one year. In the following spring, parameters of leaf length, biomass accumulation, and N content in CYS were found to be increased by COS addition under the extended photoperiod. P concentration of COS-treated seedlings was lower under longer photoperiod, but both N and P concentrations were negatively correlated with leaf length and biomass accumulation, suggesting the utilization of N and P for growth demand of CYS. The sole addition of COS mainly resulted in wholeplant P accumulation. However, when combined with the extended photoperiod, COS addition showed over-year effect on biomass accumulation and N content in CYS of transplanted Buddhist pine seedlings. Further studies are needed to confirm these results on other tree species.

Nutrient Uptake and Utilization by Fragrant Rosewood (Dalbergia odorifera) Seedlings Cultured with Oligosaccharide Addition under Different Lighting Spectra

“…We did not find a significant effect of CO addition on biomass in Fragrant rosewood seedlings. In accordance with our study, CO addition also had no effect on Buddhist pine and Northeast yew seedlings [33,34]. However, our results presented that CO addition decreased the stem sugar concentration with no effect on starch (Figure 4b).…”

“…In contrast, Wang et al did not find any significant response of RCD in current-season Buddhist pine and Northeast yew seedlings for the interaction between photoperiod and CO addition [34]. However, Wang et al reported that the interaction between CO addition and extended photoperiod in the past-season can have a continuous effect on RCD in current-season Buddhist pine seedlings after transplant [33]. Also, seedlings receiving CO addition under the natural illumination had a decreased RCD value compared to those under the extended photoperiod by HPS lamps [33].…”

“…However, Wang et al reported that the interaction between CO addition and extended photoperiod in the past-season can have a continuous effect on RCD in current-season Buddhist pine seedlings after transplant [33]. Also, seedlings receiving CO addition under the natural illumination had a decreased RCD value compared to those under the extended photoperiod by HPS lamps [33]. In addition, our results tended to contradict those by González et al [38] and Dzung et al [39], where the CO addition substantially promoted the growth of tree shoots.…”

“…Chitosan oligosaccharide (CO) is the enzymatic-hydrolyzed product of chitosan and can be used as a plant growth modifier. A recent study reported that the addition of CO to Buddhist pine seedlings during the cultural period can promote the biomass and length of newly-grown leaves after transplant through enhancing nutrient utilization [33]. Another study on current-season Buddhist pine and Northeast yew (Taxus cuspidata Siebold & Zucc.)…”

“…Chitosan is comprised of 2-acetamido-2-deoxy-β-D-glucose (N-acetyl-D-glucosamine) and 2-amino-2-de 2-amino-2-deoxy-β-D-glucan (D-glucosamine) attached via β-(1,4) linkages [33]. Chitosan oligosaccharide (CO) is the enzymatic-hydrolyzed product of chitosan and can be used as a plant growth modifier.…”