1) This study was conducted to analyze the sap flow and composition by tapping date in Acer akamotoanum from an artificial forest in the City of Jinju. The sap was collected from five saplings (diameter at breast height10-20 cm) in two phases with an interval of a month. During phase 1 (January 10, 2019 – February 9, 2019) with daily mean temperature of 1.16±2.15°C, 60.59 liters of sap was collected over 32 days. Phase 2 (February 12, 2019 – February 22, 2019) with daily mean temperature of 2.55±1.30°C yielded 13.38 liters of sap over 11 days, which was a reduction to 22% of the total sap flow in phase 1. The analysis of sugar composition in the collected sap from phase 1 and 2 showed that sucrose concentration was 2.5% at its highest during the earlier days of collection and decreased to 0.8% at the end. Glucose and fructose concentrations were measured near 0, and were lower than sucrose concentration. The most prominent inorganic elements in the collected sap were potassium (41.69 89.75 mg/kg), calcium (24.66 48.14 mg/kg) and magnesium (10.18 27.25 mg/kg). The contents of sucrose and inorganic components between the samples collected from phase 1 and 2 did not show significant differences. The sap flow amounts of A. okamotoanum from different tapping periods showed a notable variation, but there were no significant differences in the contents of sugar or inorganic elements.
Recently, cultivation and management technologies have been needed to adapt due to climate change, which is causing abnormal weather conditions. One technique is to increase the utilization of evergreen broad-leaved species with high ornamental value. A total of five treatments were installed (1m×22.5m), including 60g/m2 and 80g/m2 using two types mulching material with an overlapping and hole-drilling mulching method and these were compared to un-mulching treatment a total of planted 92m2attheWol-aTestSiteForestattheForestforBiomaterialsResearchCenterinJinju-si, Gyeongsangnam-dofor 10monthsusing3-years-oldQuercusglaucaThunb. In comparison with the control site, the 60g/m2 overlapping method was about 1.9 times higher than the root collar diameter, but there was no statistical significance between the treatments. Healthy seedlings were found to meet these conditions due to high biomass values and below and T/R ratios of 3.0 or lower and H/D ratios of 7.0 or lower. Comparing the values of LWR, SWR, and RWR, which can be evaluated for seedling due to the mulching treatments, as compared to the control, the growth of the ground areas including leaves and stems was enhanced, but the growth of the underground areas containing roots tended to have high control values. Based on this, the SQI value, which can be evaluated for the comprehensive quality of seedlings, was found to be significantly different between the control site and the mulching treatment sites, confirming that the growth and growth improvement effects were achieved with mulching treatments. The chlorophyll content analysis showed that there was a significant difference from the control site, and it was judged that weed generation in the control acted as an environmental stress, causing a decrease in chlorophyll content. It was found that the overlapping 80g/m2 of polypropylene mulching material generated about 4 times fewer weeds than the control, and the manpower required for the mulching test field and weeding were equal at 3.3 people/100m2/1 day. Mulching treatments have demonstrated a significant difference in the promotion of growth and quality of the seedlings and are judged as an alternative that can reduce the economic burden incurred by the purchase of the supplies and the manpower required to weed forestry plantations.
In this study, we targeted Pinus koraiensis container seedlings and aimed to determine the optimum light illuminance condition to cultivate healthy seedlings and establish two-storied forests. We investigated the growth characteristics and chlorophyll content of koraiensis container seedlings 2-0 growing in different light illuminance conditions of shading treatments and a control treatment. The results showed that the height and root collar diameter (RCD) growth of P. koraiensis container seedlings varied according to the shading level. The seedling height growth was highest (1.32 cm) in the control group (with no shade). The RCD growth was highest (0.35 mm) in the experimental group with 50% shading treatment (ST). The total biomass was highest (0.92 g) in the 50%-ST group, whereas the control group showed the lowest height/RCD ratio (H/RCD) of 3.39 and the lowest top dry weight/root dry weight ratio (T/R) of 1.34. The control and 50%-ST groups showed the same seedling quality index of 0.19. All indices of chlorophyll content (a, b and total) tended to increase with increasing shading rate. The study results demonstrated that a shading treatment of 50 % was optimum for the growth of P koraiensis seedlings with high shade tolerance.
Balloon flower (Platycodon grandiflorum) is a kind of mountain herbs whose roots have restorative properties and the cultivating acreage of balloon flower has been steadily increasing in Korea. More frequent rain and high amount of rainfalls as a result of climate changes predisposed balloon flower to the outbreaks of root rot at high-density cultivation area in recent years. Root crowns were usually discolored into brown to blackish brown at first and the infected plants showed slight wilting symptom at early infection stage. Severely infected roots were entirely rotted and whole plants eventually died at late infection stage. The overall disease severities of root rot of balloon flower were quite variable according to the surveyed fields in Jeonnam, Gyeongnam and Jeju Provinces, which ranged from 0.1% to 40%. The root rot occurred more severely at the paddy or clay soils than the sandy soils and their severities were much higher at lowland than upland in the same localty. The disease increased with aging of the balloon flower. The causal fungi were identified as Fusarium solani and F. oxysporum on the basis of their mycological characteristics. The optimum temperature ranges of their mycelial growths was found to be 24°C. The pathogenic characters of F. solani and F. oxysporum treated by artificial wounding inoculation on healthy roots of balloon flower revealed that F. solani was more virulent than F. oxysporum. This study identified the causal agents of root rot of balloon flower as Fusarium solani and F. oxysporum, probably for the first time.
Four-year-old seedlings of Pinus thunbergii, Pinus densiflora and Pinus rigida were inoculated with Fusarium circinatum isolate (FT-7), the pitch canker fungus, from P. thunbergii, to evaluate the effects of the pathogen on disease development and gas exchange rate. Needle dehydration was evident on 2 of 10 seedlings of P. thunbergii and P. rigida at 18 and 21 days after inoculation, respectively, while no symptoms were observed in P. densiflora seedlings throughout the experiment. Gas exchange stopped completely in 4 of 5 measured seedlings of P. thunbergii and 2 of 5 measured seedlings of P. rigida at 25 days after inoculation, and in the remaining 3 seedlings of P. rigida at 39 days after inoculation. Disease development in P. thunbergii seedlings was faster than that in P. rigida seedlings. By the time, the experiment was ended at 78 days after inoculation, 9 of 10 seedlings of P. rigida and 8 of 10 seedlings of P. thunbergii seedlings treated with FT-7 was almost dead, but all seedlings of P. densiflora were still healthy. We suggest that P. densiflora is resistant to F. circinatum in the current study, and gas exchange rate of the species after inoculation does not differ significantly compared to that of untreated control.