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Seedlings of Quercus rubra were cultivated outdoors and in a polyethylene-covered greenhouse. Their development over the first growing season was monitored and compared, taking into consideration factors such as the time of sowing (fall or spring). Height, root-collar diameter, and oven-dry mass of tops and roots were significantly greater in greenhouse-cultivated seelings. However, the differences were reduced when the seedlings were sown later in the spring. Analysis of top-root ratios showed that the balance of seedlings was not affected by greenhouse cultivation. The results of this study the rapid growth of the seedlings produced in. the greenhouse lead us to reconsider our current production standards. Key words: Grading criteria, greenhouse production, morphological quality, nursery stock. Quercus rubra, seedling production.

Measurements of leaf thickness and δ13C value were obtained for twenty species and three intergeneric hybrids of the Crassulaceae. The data include plants growing in their native habitats and also in greenhouse cultivation. There is a strong relationship between leaf thickness and leaf δ13C values. The plants with the thickest leaves of ca. 7 to 11 mm had δ13C values ranging from -11.5‰ to -13.8‰. Plants with leaves that were thinner than 2.0 mm all had δ13C values that were more negative than -23‰. Plants having intermediate leaf thickness possessed intermediate δ13C values. The leaf tissue of four genotypes spanning the range of leaf thicknesses all exhibited a two-fold or greater nocturnal increase in titratable acidity. It appears that the differences in leaf thickness and δ13C values among the tested species are genetically determined.

ÖZET Sonbahar sera hıyar yetiştiriciliğine uygun çeşit seçimi amacı ile 1983 ve 1984 Sonbaharında Antalya Maram Fı, Minibar (KO728) Fı, Hylares Fı çeşitleri ile dört tekerrürlü olarak tesadüf bloklara deneme desenine göre yapılan denemelerde Maram Fı çeşidi diğerlerine nazaran daha iyi sonuçlar vermiştir. Bu nedenle Sonbahar sera hıyar yetiştiriciliğinde Maram Fı çeşidi üreticilere tavsiye edilir. SELECTIG A CUCMBER VARIETY FOR GLASSHOUSE PRODUCTION IN AUTUMN Astudy was carried out in Antalya in autumn 1983 and 1984 with three cucumber varieties, Maram Fı, Minibar (KO728) Fı and Hlares Fı, as four replicates according to the randomized bloke design in order to select the variety that is the most suiteble for glasahouse cucumber production in autumn. As a result Maram variety proved to be the best whwn compared wtih other varieties so, Maram Fı can be recomended to the producers who wish grov cucumbers under glasss in autumn. 25

A survey is presented of the literature on greenhouse climate control, positioning the various solutions and paradigms in the framework of optimal control. A separation of timescales allows the separation of the economic optimal control problem of greenhouse cultivation into an off-line problem at the tactical level, and an on-line problem at the operational level. This paradigm is used to classify the literature into three categories: focus on operational control, focus on the tactical level, and truly integrated control. Integrated optimal control warrants the best economical result, and provides a systematic way to design control systems for the innovative greenhouses of the future. Research issues and perspectives are listed as well.

In production of Satsuma mandarin (Citrus unshiu Marc.) grown on greenhouse cultivation, management of day and night temperature and soil water content is important to improve yield and quality of the fruits. In this study, in order to optimize greenhouse environment for Satsuma mandarin production, we conducted dynamic analysis of effects of soil water content, day temperature and night temperatures on fruit growth and mass accumulation through phloem and xylem into a fruit.

収穫直前に発生するトマト果実の裂果について発生要因を探るため,埼玉県滑川町の農業生産法人において3年間の果実収量,裂果率,および当該地域の気象条件を踏まえ,温室内における気象条件の推移と裂果発生との関係について調査検討した。トマト果実の裂果は,例年4月から6月に発生頻度が高くなるが,温室内の気温および湿度が大きく変動する時期であり,1日における,気温および湿度も日ごとに大きく変動する。これら日中の気温および湿度から飽差を算出し裂果発生との関係について検討した結果,日毎の飽差の差と裂果発生との間には正の相関がみられた。このことから,裂果の発生には,飽差の変動が関与している可能性が示唆された。, Fruit cracking occurring just before harvesting is one of the most delicate problems in tomato greenhouse cultivation. In this study we investigated the relationship between fruit cracking and meteorological factors in the greenhouse. As a result, it was suggested that the sharp fluctuations of temperature and humidity of the greenhouse were closely associated with fruit cracking. In particular the vapor pressure of deficit (VPD) in the greenhouse calculated from value of temperature and humidity was indicated to have a significant correlation with fruit cracking. Therefore the control of VPD can be a possible countermeasure to suppress Tomato fruit cracking.