Internal browning is a physiological disorder affecting tomatoes (Solanum lycopersicum L.), and presents a major problem to Japanese producers. Internal browning is characterized by the discoloration (browning) of the inside of fruits while the external surface appears normal; consequently, affected fruits reach consumers without detection. Internal browning may be caused by Ca deficiency and may be suppressed by performing defoliation. We investigated the effect of defoliation on the occurrence of internal browning in Momotaro York tomatoes planted hydroponically in a glass greenhouse and in a controlled environment chamber. The occurrence of internal browning was significantly lower in the fruits of defoliated plants (50% of leaf area removed) than in the control plants (no defoliation). Moreover, the Ca content in the water fraction of young fruits obtained from defoliated plants was significantly higher than that in control plants. Overall, this study demonstrates that defoliation increases the Ca content in fruits and reduces the occurrence of internal browning in tomato plants.
This study was conducted to estimate the effects of nitrogen fertilizer application at low, moderate, and high level on photosynthesis, embryo area, and grain yield of a rice giant embryo mutant line (MGE13) in comparison with the originated rice variety Mizuhochikara (Miz). As increasing nitrogen fertilizer application, photosynthetic rate in term of the carbon dioxide exchange rate (CER) increased at the tillering, heading, and dough-ripening stages in both rice genotypes. Especially at the heading stage, the increase of CER was much higher in MGE13 than that in Miz as increasing nitrogen fertilizer from low to high level. The embryo area at both the dough-ripening and harvesting stages increased more in MGE13 than in Miz as increasing nitrogen fertilizer application level. The embryo area was significantly correlated with CER at the heading stage and with the plant growth rate during the ripening stage in both rice genotypes. Grain yield was similar in MGE13 and in Miz under low and moderate nitrogen fertilizer levels, but it was much higher in MGE13 than in Miz under the high nitrogen level, mainly due to the greater CER at heading stage, the higher dry matter weight and the larger number of panicles per plant.
In a sustainable society, it is necessary to develop systems that produce enough food and energy while also preserving the environment. Both agricultural production for food generation and photovoltaics for renewable energy production require large, open fields. In this research study, we investigate the feasibility of combining food and energy production into a single field by examining the effects of installing photovoltaic equipment above land used for farming. We grew komatsuna, kabu, mizuna, and spinach underneath photovoltaic equipment, and investigated the influence of shading from the photovoltaic equipment on plant growth and yields during winter cultivation. As expected, both the amount of solar radiation and the air and soil temperature were lower under the photovoltaics than those under the open field. The growth rate of komatsuna, kabu, and mizuna were slower. However, yields and qualities sufficient to meet market demands remained possible with extension of the cultivation periods. Therefore, although temperature and solar radiation are reduced under the photovoltaic equipment in winter, it is nevertheless possible to produce vegetables in the farmland, providing a novel opportunity to realize an integrated agricultural system with parallel production of food and energy.
Since the fruits would be apt to perishable and disease in open field cultivation of processing tomatoes, we attempted vertical double-shoots attracting cultivation to secure a stable yield in this experiment. The control plot (untreated plants) and double-shoots (cultivated by attracted 1st and 2nd lateral shoots below the top flower truss) plot were set. There was no difference between the both plots on the first flowering date. Although the number of flowers per plant was decreased significantly in the double-shoots plot compared to the control plot, there were no differences in total yield and the number of fruits. The cracked, worm-eaten, and blossom-end-rot fruits were decreased significantly in the double-shoot plot. The stem diameter, SPAD value, leaf area, and dry weight per lateral shoot were significantly larger in the double-shoots plot thanin the control, but there was no difference between the both plots in the photosynthetic rate and mineral nutrient contentsper plant. Since in the vertical double-shoots cultivation the translocation of nutrients and photosynthetic products wereincreased significantly compared to the control, we guessed the fruit productivity of one lateral shoot in the verticalcultivation would be increased compared to the untreated control cultivation.
Physical damage to strawberry fruit caused by bruising is a serious problem, and the underlying mechanisms remain poorly understood. In this study, the mechanism and location of bruising in strawberry fruit were investigated by confocal laser scanning microscopy. Observations of the three-dimensional and two-dimensional structure of the fruit surface and cross-sectional examination of the flesh and pith cells revealed that bruising is caused by external forces that induce flesh cell compression without affecting the skin surface and pith cell morphology. These results indicate that the skin that does not transmit external forces to internal tissues and the flesh cells that are not easily deformed are crucial for preventing bruising in strawberry fruit.
The influences of monochromatic light irradiation as pre-rooting treatment on the rooting of cuttings in spray-type chrysanthemum cultivars ‘Sei Prince’ and ‘Remidas’ examined using light-emitting diodes. The unrooted cuttings were irradiated with red (660 nm), green (520 nm), and blue (450 nm) light and fluorescent light at around 60 mmol m-2 s-1 of photosynthetic photon flux density (PPFD) for 24 h continuously at 20℃ for 7 days. In ‘Remidas,’ the rooting percentages of cuttings were high above 85% irrespective of light wavelength. In ‘Sei Prince,’ red light irradiation promoted the rooting of cuttings compared to the other light irradiation. When the cuttings were irradiated with red light at 59.4, 37.4, and 12.4 mmol m-2 s-1 of PPFD, a decrease in rooting percentage was not observed even at a low PPFD in ‘Remidas.’ On the other hand, in ‘Sei Prince,’ the rooting percentage of cuttings decreased at the lowest PPFD. Thus, it was shown that monochromatic light irradiation for 7 d before rooting could promote the rooting of spray-type chrysanthemum cuttings, however, not only light wavelength but also light intensity that could promote rooting differed between two cultivars.
Medicinal plants (Pinellia ternata Breit.) were cultivated under four nutrient solution conditions, namely a pH of 4 and electrical conductivity (EC) of 2.2 mS cm-1, pH of 4 and EC of 1.2 mS cm-1, pH of 6 and EC of 2.2 mS cm-1, and pH of 6 and EC of 1.2 mS cm-1. Plants were grown for 15 weeks in phytotron glass rooms controlled at an air temperature of 25℃ and a relative humidity of 70%. The leaf number per plant was measured every week, the leaf chlorophyll content (SPAD) was measured at 100 d after planting, and the corm yield and the effective ingredient, namely araban, content in the corm were evaluated after 15 weeks of cultivation. No clear effects of the nutrient solution EC and pH on the corm growth, the corm quality, and leaf chlorophyll content were not observed in this experiment. The EC and pH of the nutrient solution will not affect the productivity of the P. ternate in the ranges of EC 1.2–2.2 mS cm-1 and pH 4–6, respectively.