Intact tomato (Solanum lycopersicum L.) fruit growth was monitored while heat-girdling treatment was conducted. Heat-girdling treatments revealed that most water flow into enlarging fruit of tomato plants originated from the xylem throughout fruit growth periods. After measuring the water status and growth rates simultaneously, the growth parameters of Lockhart's equation were determined in expanding fruit of tomato plants. During the early stage of fruit growth, when the growth-induced water potential was obtained by calculating the difference between water potentials of the growing region and the water source, it was found that sizes of the growth-induced water potential and the hydraulic conductance were predominant factors to regulate cell expansion. When fruit became almost mature, sizes of the growth-effective turgor and the wall extensibility were primary factors to regulate cell expansion, but not the water potential gradients. Such changes in water flow from the xylem related to enlarging processes of fruit may explain how fruit cracking takes place right before fruit maturation.
The growth parameters of Lockhart's equation were determined in expanding leaves of tomato plants (Solanum lycopersicum L.) subjected to different relative humidity in the dark. In tomato leaves, sizes of the growth-induced water potential exhibited linear relations with the relative growth rates (RGR) under various vapor pressure difference (VPD) conditions between leaves and the ambient air. When transpiration rates of tomato plants became significantly larger, lines formed between the growth-induced water potential and RGR had a translational relation as VPD increased. Then, the transpiration-induced water potential became proportionally larger as VPD increased. These results indicated that transpiration flux and growth flux have additive relations, suggesting that water fluxes for growth and transpiration are linearly superimposed.
We examined the effects of the spectral composition conversion red film on the proliferation of protocorm like bodies (PLBs) and formation of shoots and roots in Cymbidium finlaysonianum and C. insigne in the presence and absence of benzyladenine (BA) and 1-naphthaleneacetic acid (NAA). PLBs were cultured under light provided by a cool white fluorescent light and transmitted through the red film with a 16-h photoperiod for 40 days. The addition of NAA (1 mg/L) and BA (2 mg/L) under the cover of the red film increased the number of PLBs significantly; hence, this is the most effective technique for increasing the number of C. finlaysonianum PLBs. Forty days after culture, the order of increase in the number of C. finlaysonianum PLBs was as follows: Red film+NAA+BA>NAA+BA>Red film>Control. In this study, we demonstrated that the spectral composition conversion film can be used as an alternative growth regulator for PLB proliferation in Cymbidium species.
The development of a seed-propagated cultivation system for strawberry has many advantages, including labor-saving for raising transplants and decrease in disease incidence. There are few several practical methods to prepare a large amount of high-quality seeds from strawberry fruits. We developed a new preparation method for strawberry seeds using five kinds of industrial enzymes. The effects of seed preparation methods for strawberry seeds, including the “Peeling treatment method”, “Modified blender treatment method”, “High-pressure water treatment method”, and “Enzyme treatment method” on germination performance and number of working hours were investigated. Though, there was no significant difference in the final germination percentage among the prepared seeds, the enzyme treatment method was associated with the lowest number of working hours among these methods. The effects of time and temperature during enzyme treatment on the number of seeds prepared from fruits were investigated. Even at 20°C, all the seeds were completely detached from fruits within 75 min. Enzyme treatment was possible without heating. These results indicated that the “Enzyme treatment method” could be recommended for practical use for seed preparation of the seed propagation of the type of F1 hybrid strawberry.
The present study was performed to investigate the effects of different light periods including 8, 16 and 24 h d−1 light in combination with two levels of light intensity, 100 and 200 μmol m−2 s−1 besides daily light integral (DLI; the product of light intensity and light period) on the growth and essential oil composition of Japanese mint plants (Mentha arvensis L. var. piperascens), a traditional aromatic and medicinal plant. The results revealed that growth was greatest in plants grown at 24 h d−1 light period combined with 200 μmol m−2 s−1 of photosynthetic photon flux (PPF). There was no menthofuran detected in plants under either of the applied treatments. The l-menthone and l-menthol concentrations were highest in plants treated by 16 h d−1 light period combined with 200 μmol m−2 s−1 PPF. The highest content of these compounds was produced by plants grown under DLI of 8.64 mol m−2 d−1 and more. Results revealed that light period exerts the most important effect on altering the growth and essential oil production of Japanese mint compared to light intensity and DLI.