Effect of exponential fertilization on growth and nutritional status in Buddhist pine (Podocarpus macrophyllus[Thunb.] D. Don) seedlings cultured in natural and prolonged photoperiods

Abstract

Slow growth rate limits the development of seedlings from the Podocarpaceae family. The extended photoperiod (EP) is well known to promote tree seedling growth, but it may also cause the possibility of nutrient dilution without a proper nutrient supply regime. Exponential fertilization (EF) has been proven to counter nutrient dilution within tree seedlings efficiently. However, no study has determined the response of Podocarpus seedlings to the interaction of EF and photoperiod. We fed 13-month old Buddhist pine (Podocarpus macrophyllus [Thunb.] D. Don) seedlings using EF applied at rates of 0 (control), 50 (E50), 100 (E100), and 150 (E150) mg nitrogen (N) seedling −1 for 5 months, during which half of all seedlings were cultured in the natural photoperiod (NP) with the others exposed to EP. The longer photoperiod resulted in greater seedling height and biomass accumulation of Buddhist pine seedlings. Relative to NP, EP increased N content at the whole-plant level but decreased N concentration in the stem and root, which indicated the symptom of N dilution. However, both phosphorus (P) content and P concentration increased in response to the longer photoperiod. EF rates in the E100 and E150 treatments were evaluated to be the 'sufficiency' ones for both N and P in EP and NP, respectively. In conclusion, EP could stimulate the growth of Buddhist pine seedlings but caused N dilution within them at the same time, and photoperiod would change the nutritional response of these seedlings to EF.

Prediction of Nutrient Leaching from Culture of Containerized Buddhist Pine and Japanese Maple Seedlings Exposed to Extended Photoperiod

“…needles vs. broad attributing to specific leaf area (Nagel et al, 1998). In contrast to our results of the null response of Buddhist pine seedlings to photoperiod, an earlier study suggested a stimulated response to height of juvenile Buddhist pine seedlings in response to extended photoperiod (Wei et al, 2013). The most reasonable explanation of these varied responses can be concluded due to the difference of lightsensitivity driven by plant developmental stages.…”

“…Because leachates were collected by traits immediately after irrigation until the volume of 100 mL, therefore declined P loss may result from increased P uptake by seedlings of the two species under extended photoperiod. Wei et al (2013) revealed that under extended photoperiod P uptake was fully promoted by needles, stem, and root of Buddhist pine seedlings. Accordingly, photoperiod was also found to affect P requirement for the maximum growth rate (Shatwell et al, 2014).…”

“…The most reasonable explanation of these varied responses can be concluded due to the difference of lightsensitivity driven by plant developmental stages. Wei et al (2013) used Buddhist pine seedlings cultured from germination, thereafter initial and terminated height of Table 5: Pearson correlations between nutrient concentrations of phosphorus (P), potassium (K), ammonium-nitrogen (N), and nitrate-N and height and root collar diameter (RCD) of seedlings of Japanese and buddhist pine cultured with three sizes (Large, medium, and small) of containers from 11 to 25 Nov. 2014 seedlings was about ~6 cm and ~14 cm, respectively. In our study, seedlings cultured for one growing season had initial and terminal height of ~14 cm and ~26 cm, respectively.…”

“…This argument cannot be proved to be null on the basis of current evidence, because the general aim of performing an extended photoperiod is to promote tree growth. Hence, relevant studies have paid too much attention to determine tree-responses, such as morphology (Wheeler, 1979;Bongarten and Hanover, 1985), biomass accumulation (Macey and Arnott, 1985;Johnsen and Seiler, 1996), photosynthetic rate (do Amaral et al, 2006), nutrient uptake and reserves (Wei et al, 2013). As a result, information about leaching characteristics beneath containerized seedlings subjected to an extended photoperiod is quite limited.…”

“…The inherent affectivity works through the mechanism of a longer term of photosynthetic product synthesizing per day. A recently published study determined that an extended photoperiod could successfully promote seedling growth of Buddhist pine (Podocarpus macrophyllus), a slowly growing species mainly used as an ornamental tree (Wei et al, 2013). Compared to the naturally regular illumination-time, the employment of the extended photoperiod has the reasonable potential to control nutrient loss in leachates because under an extended illumination root proliferation can be benefited from photosynthetic production and absorbed more nutrients detained within containers.…”