Yurina Kwack

Comparative anatomy of embryogenic and non-embryogenic calli frompimpinella brachycarpa

Anatomical differences between embryogenic and non-embryogenic calli ofPimpinella brachycarpa were investigated by light microscopy and electron microscopy. Initial callus tissue emerged from expiants after 14 d of culturing. The embryogenie calli (EC) were firm, rather opaque, and light yellow in color. The cells usually formed small, compact clusters. Nonembryogenic calli (NEC), however, were friable, semitransparent, and yellow or gray. These formed relatively larger and loosely held clusters. Scanning electron microscopy showed that EC were composed of individual compact and spherical cells that were rather regular in size and approximately 20 µm long. All were tightly held together and appeared to organize globular embryos. In contrast, the NEC comprised elongated and loosely held cells that were approximately 50 µm long. Tubular and u-shaped NEC cells protruded irregularly, and were of varying heights along the cell aggregates. Transmission electron microscopy of the EC revealed typical eukaryotic cytoplasmic components, including nuclei, mitochondria, and vacuoles in the cytoplasm enclosed by an electron-transparent cell wall. Based on the numerous ribosomes within the cytoplasm, these cells appeared to be well-organized and metabolically active. The NEC cells were much larger and more highly vacuolated than those of the EC. In ultrathin sections, the former seemed to be almost devoid of other cellular contents except for plastids and nuclei. Furthermore, EC and NEC showed different regeneration capacities in their somatic embryo formation. Most EC produced hyperhydric somatic embryos, followed by normal somatic embryos; whereas only a few shooted or rooted somatic embryos arose from the NEC.

Root-zone cooling affects growth and development of paprika transplants grown in rockwool cubes

The possibility of improving the efficiency of transplant production during a summer season was studied by applying partial cooling of the root-zone during the cultivation of paprika transplants in a greenhouse. Paprika seedlings produced in a closed transplant production system were transferred to rockwool cubes, and cool-water circulation systems using plastic and stainless pipes were tested in a greenhouse during a summer season. The root-zone temperature of rockwool cubes and growth and development of paprika transplants as affected by root-zone cooling were investigated. When plastic pipes were used, the cooling efficacy by circulation of cool water (17°C) was the greatest and the temperature of rockwool cubes decreased by 3.6°C during the day time on a sunny day. Partial cooling of the root-zone enhanced root growth and increased number of flowers as compared with the transplants grown on uncooled rockwool cubes. The results indicate that partial cooling of the root-zone can alleviate damages to transplants commonly caused under high air temperature conditions, which could efficiently improve the paprika transplant production efficiency in greenhouses during the summer season.

Growth and quality of sprouts of six vegetables cultivated under different light intensity and quality

Vegetable sprouts (alfalfa, broccoli, clover, kohlrabi, radish, and red radish) were cultivated under three monochromatic light regimes (red, green, and blue) with five different light intensities (0, 12.5, 25, 50, and 100 µmol·m−2·s−1) to investigate the effects of light intensity and quality on the growth and total phenolic content of the vegetable sprouts. The light quality and intensity had a direct effect on hypocotyl elongation in vegetable sprouts. Increasing blue light intensity enhanced suppression of hypocotyl elongation in all of the vegetable sprouts. Red light also reduced hypocotyl length in alfalfa and clover sprouts comparing those grown in darkness. The fresh weight of broccoli and radish sprouts markedly increased when red light intensity was 100 µmol·m−2·s−1; however, light use efficiency (LUE) decreased with increasing light intensity. Total phenolic content was reduced by increasing red light intensity in alfalfa and red radish sprouts.

Comparison of Six Spent Mushroom Composts As Growing Media for Transplant Production of Lettuce

We investigated the physical and chemical properties of six spent mushroom composts (SMCs) and addressed the possibility of reusing SMCs as growing media for transplant production by comparing the seed germination and growth characteristics of lettuce transplants grown in the SMC-based media. The tested SMCs were collected from factory-like mushroom production systems that produced major mushrooms, such as Agaricus bisporus, Flammulina velutipes, Pleurotus eryngii, Hipsizigus marmoreus, Grifola frondosa and Pholiota nameko. We used SMCs discharged from factory-like mushroom production systems because of their year-round uniformity in composition. SMC uniformity is critical for plant growing media used in transplant production that requires highly sophisticated control of edaphic environments. The six tested SMCs had a higher nutrient content than the commercial medium and the bunasimezi SMC had the highest bulk density. The pH and EC of the white button mushroom SMC were higher than those of other SMCs. Lettuce transplants grown in the white button mushroom SMC had a high seed germination and early growth, similar to results obtained with commercial medium. The use of bunasimezi SMC resulted in the smallest percentage of germination and retarded early growth.

Growth and Quality of Baby Leaf Vegetables Hydroponically Grown in Plant Factory as Affected by Composition of Nutrient Solution

The objective of this study was to investigate the effects of composition of nutrient solution on the growth and quality of baby leaf vegetables (tat soi, romaine lettuce, beet, and red radish) hydroponically cultivated in plant factory. The seeds of four vegetable crops were sown in urethane sponges and cultivated for 14 days in a plant factory. Light intensity and photoperiod were 110μmol·m·s and 16 h, respectively; and air temperature in photo/darkperiod was maintained at 25/20C. Tap water was used for irrigation for 7 days after sowing, and then plants were irrigated for 7 days using tap water and the nutrient solutions of Korea Wonshi, Japan Enshi, and Yamazaki for lettuce. At 14 days after sowing, the fresh weight of tah soi was highest in the nutrient solution of Yamazaki for lettuce, and there were no significant differences among nutrient solutions in beet and red radish. When we compared leaf color using Hunter’s a value, the nutrient solution of Korea Wonshi and Japan Enshi increased green color in baby leaf vegetables, while the nutrient solution of Yamazaki for lettuce increased red color. Total phenolic content of romaine lettuce was highest in the nutrient solution of Korea Wonshi, but tat soi, beet, and red radish showed no significant differences among nutrient solutions in total phenolic contents. From these results, we suggest that using the nutrient solution of Korea Wonshi can enhance the growth and quality of romaine lettuce and the nutrient solution of Yamazaki for lettuce is appropriate for enhancing the growth and red color of beet and red radish in plant factory. Additional key words : Japan Enshi, Korea Wonshi, leaf color, total phenolic content, Yamazaki for lettuce

Proper period and temperature for transportation of cucumber and tomato transplants

With an increased demand for high-quality transplants, vegetable growers have begun to purchase grafted transplants from specialized propagators. These are often shipped over long distances, but improper transport conditions can deteriorate transplant quality. To determine the appropriate period and temperature for transporting grafted transplants, we stored cucumber and tomato transplants in darkness at 6, 9, 12, 15, and 18 o C for 3, 6, 9, 12, and 15 days, and subsequently cultivated these in a greenhouse for 15 days. We investigated the changes in plant height and SPAD value during storage, as well as the early growth of the stored transplants during subsequent cultivation. Increasing temperature during storage promoted stem elongation in both transplant species, with cucumber transplants showing greater stem elongation than tomato transplants. SPAD values of cucumber and tomato transplants tended to decrease with increasing storage temperature, declining even further with extended storage period. The cucumber transplants stored for 3 days and the tomato transplants stored for 6 days, showed no decrease in percent survival and no delay of growth after transplanting compared with non-stored transplants. From these results, we suggest that the appropriate temperature for transporting cucumber and tomato transplants in darkness is 6°C, and the appropriate period of storage in darkness are 3 and 6 days for cucumber and tomato transplants, respectively. Controlling transportation conditions can avoid the deterioration of transplant quality during transport and the delay of early growth after transplanting.

Optimum Cultivation Period and Rockwool Block Size for Paprika Transplant Production using a Closed Transplant Production System

This study was conducted to investigate the effect of cultivation period and rockwool block size on the growth and early yield of paprika transplants grown in a closed transplant production system. Paprika seeds were sown and germinated in three different size of rockwool blocks (45 × 40 × 35, 70 × 70 × 60, 100 × 100 × 65 mm) and cultivated in a closed transplant production system for 23, 30, and 37 days after sowing. Paprika transplants were cultivated using 100 × 100 × 65 mm rockwool blocks in a greenhouse following a conventional and typical production method for comparing with the growth of paprika transplants grown in a closed transplant production system. Also, we transplanted paprika transplants grown for 23, 30, and 37 days in a closed transplant production system and greenhouse to rockwool slabs and investigated fresh weight of fruits and yield 125 days after sowing. The growth of paprika transplants grown in 70 × 70 × 60 mm rockwool blocks in a closed transplant production system was highest, and the quality of paprika transplant grown in a closed transplant production system was better than in a greenhouse. Rockwool block size and cultivation period in a closed transplant production system did not affect fresh weight of fruits, however, yield was largest when paprika transplants were cultivated using 70 × 70 × 60 and 100 × 100 × 65 mm rockwool blocks for 23 days in a closed transplant production system. These results suggest that decreasing rockwool block size and cultivation period can be strategically used to enhance transplant quality and yield of paprika, as paprika transplants were cultivated in a closed transplant production system. Additional key words : Capsicum annuum L., greenhouse, root-zone volume, seedling