Noriko Takahashi

Silica Distribution on the Husk Epidermis at Different Parts of the Panicle in Rice (Oryza sativa L.) Determined by X-ray Microanalysis

Compared with other crops, rice (Oryza sativa) accumulates considerable amounts of silica on the surface of its husk or leaf (Takahashi et al., 1990) and numerous studies on the benefi ts of Si have been conducted in rice and other plant taxa (Yoshida et al., 1959; Jones et al., 1967; Epstein, 1994, 1999; Savant et al., 1997). Although silica is not considered necessary for plant growth or production, the cuticle-silica layer of epidermis helps rice plants maintain erect leaves, reduce transpiration and protects the plants from disease and insect pests (Iwata et al., 1961; Maxwell et al., 1972; Agarie et al., 1992, 1998; Ma, 2004). Ueno et al. (2005) found that silica defi ciency in the cell walls of stomatal apparatus increased evaporative water loss from the rice leaves. Water loss from the panicle of rice is primarily controlled by the cuticlesilica layer on the epidermis of the husk. Given that rice husks, unlike leaves, lack stomata and thus have no dynamic water conservation mechanism, glumes and anthers are subjected to severe desiccation, which contributes to reduced fl owering and high sterility of the panicles (Ekanayake et al., 1989, 1993). Therefore, the water status of the panicles needs to be analyzed in detail to determine the mechanism of rice sterility. The transpiration rate and silica concentration/distribution on the epidermis of the husk are the two main factors that determine the water states of the panicle, because silica is considered to suppress the transpiration from the husk. Silica is transported by the transpiration stream and is deposited at places where transpiration occurs. Consequently, the distribution of silica in the rice plant may indicate specifi c sites of high transpiration rates or water loss (Dikeman et al., 1981; Balasta et al., 1989). Soni et al. (1973) reported that silica distribution on the epidermis of the rice husk was uneven and observed heavy silica deposition on the papillae, which presented on the margins of the husk. However, differences in silica concentration/distribution on the epidermis of husks in relation to their position in the panicle have not been reported. The distribution of Si can be determined by X-ray microanalysis. For example, X-ray microanalysis revealed the deposition of silica in the outer walls or leaf epidermis in rice (Lux et al., 1999), sorghum (Lux et al., 2002), and bamboo (Lux et al., 2003). The objective of the present study was to investigate the differences in silica concentration/distribution on the epidermis of husks at different parts of the rice panicle at the fl owering stage using scanning electron microscopy (SEM) combined with energy dispersive X-ray (EDX) microanalysis.

Effects of Elevated Atmospheric Carbon Dioxide Concentration on Silica Deposition in Rice (Oryza sativa L.) Panicle

Abstract The effects of elevated carbon dioxide concentration ([CO2]) on silica deposition on husk epidermis of rice (Oryza sativa L. cv. Akitakomachi) during the flowering stage were investigated in this study. The study was motivated by the concept that the rice yield maybe affected by global warming as a result of elevated [CO2] environment since sterility of rice is related to the panicle silica content that influences transpiration, and elevated [CO2] could affect plant transpiration. Silica deposition analysis was focused on the flowering stage of the rice crop grown hydroponically under two [CO2] conditions: 350 μmol mol-1 (ambient) and 700 μmol mol-1 (elevated). Silica deposition on the husk epidermis from three parts of the panicle at four flowering stages were examined using a scanning electron microscope (SEM) combined with an energy dispersive X-ray microanalyzer (EDX). The results demonstrated that elevated [CO2] significantly suppressed silica deposition on the husk epidermis at the lower part of the panicle, and at the early flowering stage when 1/3 of the panicle emerged from the leaf sheath. In the transverse section analysis of the husk, silica deposition on the husk epidermis under elevated [CO2] was less than that under ambient [CO2] at the late flowering stage. The less silica deposition observed on the husks at the late flowering stage under elevated [CO2] might be related to the suppressed transpiration from the panicle by elevated [CO2] found in a previous study.

Evaluation of Tomato Fruit Color Change with Different Maturity Stages and Storage Temperatures Using Image Analysis

Abstract The effects of storage duration and temperature on the tomato fruit color change and quality with different maturity stages tomato were investigated in this study. Tomatoes were grown hydroponically in high technology greenhouse. Tomato fruit samples with green to red were stored in cool incubator for 48 h. The storage temperature was adjusted at 15 °C and 20 °C. The maturity stage of tomato fruit was evaluated with chiromaticity by image analysis. Little tomato fruit color change with storage was observed in large maturity stage (red fruit) regardless of storage temperature. Chromaticity in small maturity stage (green fruit) was increased with storage time. The sugar content of fruit was increased and fruit firmness was decreased with storage at both temperatures for 15 °C and 20 °C regardless of maturity stage.

Effects of Serum Vitamin A Level on Tapetum in Japanese Black Cattle Eye

Abstract The relationship between serum vitamin A level and tapetum reflection was investigated using ultraviolet imaging. The tapetum was obtained from eyes of slaughtered cattle in which the serum vitamin A level was below 50 IU/dl. The tapetum reflection was examined in the tapetum lucidum, tapetum nigrum, and optic disc. For each part, the tapetum reflection decreased with increasing serum vitamin A level. A high tapetum reflection value might represent the bleached tapetum symptom that occurs because of the low serum vitamin A level.

Considerations for Accurate Whole Plant Photosynthesis Measurement

Whole plant photosynthetic rate (Pn) measurements provide an integral assessment of how an entire plant responds to biotic and abiotic factors. Pn determination is based on measurements of CO2 exchange rates (CER) which can be determined using various types of systems including Closed, Semi-closed, and Open systems. This review focused on important design and operational considerations of Open CER measurement systems. Key mechanical and biological factors that may influence measurement accuracy include leakage of a chamber, CO2 differential between air inlet and outlet of a chamber, chamber air humidity, canopy air speed, acidity of growth media and irrigation water to name a few. Proper design and operation of a whole canopy photosynthesis system are necessary to assure accuracy of the Pn measurements that may be used to assess both short term responses and long term yield of a plant as a result of given stimuli.

Development of a Multi-Operation System for Intelligent Greenhouses

Abstract To resolve the problem of declination of Japanese agriculture, plant factories with automation, quality control, robotization and speaking plant approach are necessary. The multi operation system described in this paper has running unit with automatic position sensing. Growth environment measurement unit has transpiration, photosynthesis, distance and temperature sensors to obtain plant growth information. The pest control unit uses the antiseptic effect of ozone water. The harvesting unit is used for cucumbers that grow fast; recognition of cucumbers ready to be harvested is achieved through distance information gathered by an attached photo interrupter and distance sensors. The development of multi-operation robot is continued by developing controlling program that can change the operating pattern by sharing the contents by each controlling and operating unit.

Plant Diagnosis by Monitoring Plant Smell: Detection of Russet Mite Damages on Tomato Plants

Abstract Sensor-based plant diagnosis techniques to monitor plant physiological status are important for agricultural production in highly sophisticated greenhouses. Plants emit a broad range of volatile organic compounds and its emission profile changes depending on the plants physiological status. We demonstrated a detection of tomato russet mite damages occurred on stems of tomato plants grown in a semi-commercial greenhouse with an inexpensive- and handy- gas analysis instrument. The results proved that the tomato russet mite damage significantly decreased the amount of terpenes stored in trichomes on the main stem.

Root Temperature Control System Using Cold Water in Greenhouse

Air temperature in greenhouse is high for tomato plants in summer. It is important to maintain optimum temperature in greenhouse for yield. The cost of whole cooling in greenhouse is so expensive that local temperature control is suggested. Our previous research showed tomato plants with root cooling at 25 °C increased yields compared with those with no cooling. The chilled water can be used for root cooling system in greenhouse. The objective of this research was to evaluate the root cooling system using cold water for growing tomato plants in summer. Tomato plants were grown hydroponically in greenhouse. The cooling water flows into PVC pipe which is installed under cultivation bed. Water temperature was maintained at 12 °C. Inlet and outlet water in pipe and rockwool temperatures were measured. Our results showed that the rockwool temperature was maintained around 22°C with high air temperature (30°C) using root cooling system.

Serum Vitamin A Level Measurement in Beef Cattle Using Ultraviolet Camera

Serum Vitamin A level is important indication to control the beef quality in Japan. The beef quality depends on serum vitamin A (VA) level. From 16 months to 24 months, serum VA level should be maintained low level and kept at about 30 IU/dl to produce the high quality meat.It is need to control serum VA level without cattle diseases. Generally, serum vitamin A level is mainly detected by blood assay. However, it is time-consuming, expensive, and stressful to the cattle. Therefore, a non-invasive, rapid, and simple method for monitoring serum VA level is desirable to produce the high quality beef. In the previous study, pupil reflection was related to the serum VA level. The photosensitive pigment rhodopsin related to serum VA has an absorption about 380nm, so it would appear that there is the relationship between pupil reflection in 375nm-wavelength and VA level in blood. The objective of this study was to predict serum VA level with pupil reflection using ultraviolet (UV) camera. Materials were eye balls from 32 live Japanese black cattle and 22 slaughtered cattle. The positive correlation between pupil reflection and VA level was observed in live cattle, whereas the negative correlation between tapetum reflection and VA level in slaughtered cattle was found. These results suggested that LED light doesn’t reach tapetum and it seems to be difficult to get the tapetum information from pupil images.

Local temperature control within a confined space

Abstract Precision agriculture is now practiced in plant factories. Microprecision techniques to manage temperature or other parameters in the plant factory can provide objectively controlled environments for specific purposes. This paper discusses an experiment to control local temperatures, as an example of how microprecision technology can be implemented in plant factories. This technique can also be implemented in peoples living and working environments