Many important agronomic species grown in temperate climates have been imported from warmer tropical and subtropical habitats. Unlike native temperate climate species, most plants from warm climate evolutionary origins have very little capacity to acclimate to cool much less freezing temperatures. Because the cool temperature sensitivity of these crops plays a central role in determining the growing range as well as annual variations in their economic success, there is intense interest in discovering the mechanistic bases for low temperature sensitivity. It is hoped that by defining the primary chilling-induced lesions that cause the metabolic dysfunctions in warm climate plants that it will be possible to devise strategies to minimize the sensitivity. However, the relevant physiological bases of chilling sensitivity depends critically on the seasonal climatic conditions of the target growing region, whether the low temperature episodes occur at night or in the light, as well as on the species of warm climate plant under consideration. These issues are considered in the context of what is currently understood about the underlying mechanisms of chilling sensitivity.

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Modern marketing chains continuously stimulate postharvest technology research to develop and improve techniques for measuring internal defects and nutritional and organoleptic fruit quality attributes. Three relatively new non-destructive techniques to assess pear fruit quality and to determine the optimal harvest date-acoustic firmness sensor, electronic nose and near-infrared spectroscopy-are described here. Tomographic techniques like X-ray computer tomography and magnetic resonance imaging were found to be useful for detecting the incidence of core breakdown, a storage disorder in Conference pears. Both techniques were found suitable to discriminate between cavities, affected and unaffected tissue. An attempt was made to detect internal cavities using a technique based on vibrational modal analysis.

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A sufficient balance in the supply and loss of water is an important prerequisite for the occurrence, growth and productivity of plants. For a higher plant, the water balance is given by the difference between water uptake across the root and water losses by transpiration in the shoot. Much is known about the mechanisms used by plants to minimize water losses across stomata. For technical reasons, much less is known about the input side of the balance, i.e. about the regulation of water uptake from the soil. Results are summarized on water uptake in great detail (cell, tissue, organ, and whole plant levels) . Experimental findings result in models of the water transport across roots which incorporate molecular mechanisms, i.e. the gating of water channels (aquaporins) by different external and internal factors. The recent criticism of the cohesion theory of the ascent of sap in plants is discussed. Recent results support the theory. They show that the evidence gainst the theory was based on artifacts. Overall, there is support that, to some extent, plants behave like“hydraulic machines”and that water flow within plants may be described by just a few physical principles.

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Greenhouses are complex systems with many variants and many different user requirements. Modern technologies are cost effective and very powerful to meeting diverse user control and management requirements. Optimization tools are making analytical and expert methods practically applicable. The system described features generalized functions for process control, configurable to meet greenhouse control requirements. Intelligence is shared among low level control loops in the controller and high level decisions made at the central process computer. An open Knowledge Based System, in the form of tasks and subtasks, provides an elegant way of rapid program development. Fuzzy decisions and fuzzy controllers at the supervisory level can provide adaptive reference (set-point) generators, which are key elements for near-optimal greenhouse control. The system is also equipped with an on-line process optimization tool, which was built based on a modified search algorithm with accelerated learning. Each process when entered under the optimizing monitor, is performance driven, conducts real experiments on the site and uses a modified descent method to maximize performance. An adaptive system guides the selection of control parameter values on-line, in a process searching for the global minimum of the cost function. This paper presents the general features of the system, how it can be set-up to achieve specific goals and presents results of tests conducted for low, medium and high level control and supervision.

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In an effort to gain an understanding of the processes governing matrix-assisted ultraviolet laser desorption/ionization (UV-MALDI), we made a direct comparison of the mass spectra of synthetic (PEG, PMMA, PS, PDMS) and bio-polymers (neutral cyclic and acyclic, sulfated and basic mono- and polysaccharides) by using nor-harmane and gentisic acid (GA) as UV (337 nm) -MALDI-TOF-MS matrices in positive and negative ion modes in linear, reflectron and post-source decay (PSD) modes. The majority of the examples discussed shows nor-harmane working better as matrix than GA. This peculiarity is quite noticeable in negative ion mode. Because the initiation of the UV-MALDI process is a photochemical reaction (matrix+hν (337 nm) → matrix), the acid-base character of nor-harmane in the ground and the lower electronic excited singlet state, together with other photophysical properties are discussed in brief. Excellent results obtained with commercial synthetic polymers and commercial cyclodextrins with nor-harmane allow us to propose these analyte-matrix systems for UV-MALDI-TOF-MS calibration in positive and negative ion modes in linear, reflectron and PSD modes.

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Image system recognizing the position of the fruit with the preparation of the manipulator is necessary for the development of the robot automating for the harvesting of the tomato. When there is only one fruit, it is easy work, because the red color may be searched. Actually, there are many mature and immature fruits together on the branch. The quality deteriorates, when immature fruit is injured. It is important to harvest only the matured fruit without injuring another fruit. It is necessary to harvest from the fruit in the front, when there is a fruit in multiple conditions. The thermal image was utilized in order to recognize the mature and immature fruit. And, it was developed and was utilized by the new wire size reduction method in order to separate multiple fruits. As the result, it succeeded in the separation of the fruit.

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In order to develop an irrigation control system for applying optimum water stress to produce high-Brix tomato fruits with restricted root-zone hydroponics, a non-destructive evaluation method of water stress by measuring stem diameter (SD) was investigated. SD was continuously measured by using a laser sensor at internode between the 2nd and the 3rd leaves of tomato plant during the growing period. Relative stem diameter (RSD) was used as an index of a water stress, which is calculated from a percentage of SD toward maximum stem diameter (MSD) . When RSD is 100%, there is no water stress. And if the RSD is smaller than 100%, an intensity of water stress is bigger. RSD indicated a diurnal change which decreased to less than 100% after the sunrise and recovered to 100% from the evening to midnight. With a substrate drying, the relationship between RSD and leaf photosynthetic rate (Pr) was expressed as linear regression lines with high coefficient of correlation. The positive correlation between RSD in one plant grown in cultivation bed and relative water content (RWC) of leaves in other plants was investigated, except for the harvesting time of the double-truss cultivation. These results indicate that RSD is useful for an evaluation of water stress as an index for irrigation control in tomato cultivation, while a time constraint should be concerned in evaluating water stress by RSD measured at same stem position.

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Irrigation control system using relative stem diameter (RSD) as the index of water stress was developed to stabilize a tomato production of high-Brix fruits by restricted root-zone hydroponics. This experiment has been conducted to investigate the effectiveness of this irrigation control system on characteristics of growth, yield and fruit quality of tomato plants. In this control system, irrigation starts when RSD is lower than the set point (SP) in the irrigation time period. Irrigation timing has been controlled with high SP (H-SP) and low SP (L-SP) in double-truss tomato cultivation by the hydroponics. As a result, RSD, amount of irrigation, plant height, leaf area, total fruit number and weight in L-SP were smaller than those in H-SP. However, Brix and acid content of tomato fruit in L-SP were higher than those in H-SP. Although a significant positive relationship was observed between evapotranspiration rate and amount of irrigation during growing period, the correlation coefficient in L-SP was higher than that in H-SP. These results suggested that amount of irrigation in L-SP was controlled with evapotranspiration rate under high intensity water stress and that application of optimum water stress by this irrigation control system was effective for the tomato production of high-Brix fruit.

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Meristem tissues removed from aseptically cultivated tomato seedlings were treated with two chemical mutagens, and the growth and differentiation or morphological changes of the mutagen-treated leaf primordia were traced in developed leaves. The morphological variations were most frequently detected in the leaves developed from meristems treated withN-methyl-N'-nitro-N-nitrosoguanidine at 100 μg/ml. The variegated leaves were cultured on MS medium supplemented with 2.0 μg/ml BAP for in vitro isolation to multiply morphologically altered tomato plants. The calli were obtained from the leaves and successfully differentiated to plants with the variegated leaves. Consequently, the regenerated plants produced variegated leaves similar to that originally used for tissue culture. The present results suggest that the present method to apply chemical mutagens is to induce variegated leaves and to multiply their regenerants in vitro.

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This experiment was carried out to determine the effect of low light intensity from May 15 to August 31 (3.5 months) on the growth of mericlonedCymbidiumorchid. In the two cultivars (Cymb. Rose Wine‘Fruity Drop’ andCymb. Great Katty‘Little Louransan’) that were grown under shaded conditions for the period, their fresh weight was lower than the control's, especially the root's, which was more than 50% lower at 3 months after the low-light treatment. The number of leaves and leaf length were also smaller even 1 year after treatment. In regard to leads, shadedCymb. Rose Wine‘Fruity Drop’ showed much reduced development of new lead, and the ratio of plants that developed no lead was also higher in comparison with the control. ForCymb. Great Katty‘Little Louransan, ’ the ratio of plants that developed new leads was not different between the treatment, but their growth was poorer in shaded plant.

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Avocado (Persea americana), papaya (Carica papaya) and mango (Mangifera indica) fruits were separately sealed in low-density polyethylene (LDPE) packages and stored for 8 or 12 d at 20°C to study the effects of ethylene removal on changes of gas concentrations and retaining freshness of the fruits under modified atmosphere packages (MAP) . Although the varying inclinations of steady-state O₂and CO₂partial pressure in packages with ethylene absorbent (treatment) for various fruits were about the same those in packages without ethylene absorbent (control), steady-state ethylene concentrations in the control were found to be the highest for avocado fruits and lowest for mango fruits. In this experiment, it was shown that there were few effects of ethylene removal on the appearance of browning or yellowing of the fruit skins and softening of the fruits, but decay of the fruits was inhibited for up to 8 or 12 d storage.

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The effects of CO₂enrichment on growth rate and flowering were investigated inSonerila picta, a Melastomataceae species. The plant height, leaf number, branch spread and root growth increased under 1200 and 2100 ppm CO₂compared with those in ambient CO₂ (340-450 ppm) . Flowering was advanced by 7d and number of florets per plant increased by 70% under 1200 and 2100 ppm CO₂. The increase in florets under CO₂enrichment may be related to increased number of mature branches and increased flowering percentage of the flower buds that differentiated on the branches. The CO₂enrichment is useful to improve the growth rate and flower quality ofS. picta.

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