To investigate the impact of nitrogen (N) mineral on reproductive potential of Brassica napus L, plants were treated with different levels of N treatment (N0; N100; N500). The half of N content for each treatment were applied at the beginning of the early vegetative stage and the rest was applied at the late vegetative stage. Nitrogen content in plant tissues such as root, stem and branch, leaf, pod and seed was analyzed and harvest index (HI) was calculated as percentage of seed yield to total plant weight. Biomass and nitrogen content were significantly affected by different levels of N supply. Biomass was significantly decreased by 59.2% in nitrogen deficiency (N0) but significantly increased by 50.3% in N excess (N500), compared to control (N100). Nitrogen content in all organs was remarkably increased with nitrogen levels. N distribution to stem and branches, and dead leaves was higher in N-deficient (N0) and N excessive plants (N500) than in control (N100). However, nitrogen allocated to seed was higher in control (N100) than in other treatments (N0 or N500), accompanied by higher HI. These results indicate that the optimum level of N supply (N100) improve HI and N distribution to seed and excessive N input is unnecessary.

The Sasa quelpaertensis Nakai is a white band on the edge of the leaf, the branch is not split, the stem is small, and the shape of the node is different from that of the inland bamboo (Sasa borealis Makino). It is known as a plant that is highly likely to be used as a resource plant. Various efficacy studies such as antioxidant, anti-obesity, antibacterial and antidiabetic activities have been conducted and developed as functional cosmetics and beverage products. Unfortunately there is little research on the suitability of the product. In order to use S. quelpaertensis as a raw material for food or health functional food, S. quelpaertensis leaves were collected monthly for one year to prepared 70% ethanol extract(SQEP) and water extract(SQWP). After, the content of index component(p-coumaric acid) in SQEP and SQWP was analyzed by HPLC. For the study of the processing properties, the SQWP was prepared considering the content of the index component and extraction yield(%). Also, the stability of index component according to pH(2.5, 4.0, 6.0, 8.0, 10.0) condition and stability of index component according to temperature condition(25℃, 35℃, 40℃) were studied. Through this process ability(properties) study, we suggest that the SQWP may be used as a product material of health functional foods.

Planting date of soybeans [Glycine max (L.) Merr.] is one of production components in cultural systems. The objective of the current study was to identify the components of soybean production and cultural practices encompassing planting dates and cultivars that respond to dry matter accumulation, harvest index and yield components. Three determinate soybean cultivars were planted on May 13 (early), June 3 (mid), and June 24 (late). Planting density was 60~times 15cm with 2 seeds (222,000 plants per ha). Soybean plants were sampled every 10 days interval from the growth stages of V5 to R8 and separated into leaves including petioles, stems, pods, and seeds. Dry matter accumulations, harvest indices, and yield components were measured. Early planting had taken 55 days from VE to R2 and late planting taken 39 days indicating reduced vegetative growth. Early planting showed higher leaf, stem, pod and seed dry weights than late planting. However, late planting appeared to be higher harvest index and harvesting rate. Vegetative mass including leaf and stem increased to a maximum around R4/R5 and total dry weight increased to a maximum around R5/R6 and then declined slightly at R8. The highest seed yield was obtained with mid planting and no difference was found between early and late plantings. Cultivar differences were found among planting dates on growth characteristics and yield components. The results of this experiment indicated that soybean yield in relation to planting dates examined was mainly associated with harvest index and harvesting rate, and planting date of cultivars would be considered soybean plants to reach the growth stage of R4/R5 after mid August for adequate seed yield.

This experiment was conducted to investigate the changes of harvest index and the relationship between harvest index and yield determination factors by different planting times in the determinate soybean cultivars, Shinpaldal and Danbaeg. Optimum planting were 23 May in 1995 and 1996. Late planting were 13 June in 1995 and 6 June in 1996. Growth period from planting to physiological maturity (R7) was shortened as planting time was delayed in two cultivars due to shortening of reproductive growth period in Shinpaldal, and of vegetative growth period in Danbaeg. Stem weight was distinctly decreased in late planting compared to optimum planting, but seed weight of both cultivars was not different between planting times. Also, seed number per pod and harvest index were significantly increased in late planting and the high correlation was found between two factors. It was suggested that increase of harvest index in late planting would be related with high assimilate use efficiency due to increase of sink capacity. The results of correlation and principal component analysis for yield determination factors showed that main factor on yield determination was pod number per plant at R5 stage associated with dry matter accumulation during early reproductive growth period, seed number per pod and harvest index were the second factor, and one hundred seed weight was the third factor. The result of this experiment indicated that yield determination in soy-bean was dependent mainly on pod number per plant related to dry matter accumulation by early reproductive growth period, and the increase of seed number per pod and harvest index could compensate for yield decrease by shortening of vegetative growth period in late planting. Such result suggests that optimum planting date can be delayed from mid May to early June in improved soybean cultivars in Korea