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Effects of Growth Conditions on External Quality of Cut Chrysanthemum

其他書名	Analysis and Simulation
出版	Wageningen Universiteit, 2003
ISBN	90580882199789058088215
URL	http://books.google.com.hk/books?id=-sftAAAACAAJ&hl=&source=gbs_api

註釋The effects of the assimilate availability on the NoF, individual flower size and plant height is described in Chapter 4.1. Seven greenhouse experiments were conducted in different seasons using the cultivar 'Reagan Improved' (spray type). One extra experiment was carried out to extend this study to two other cultivars ('Goldy' and 'Lupo': 'santini' type), focusing on their response to plant density. Assimilate availability, measured as total plant dry mass (TDM, g plant sup-1/SUP), increased with higher light intensity, higher CO 2 concentration, lower plant density or longer duration of the LD period. In contrast, variation in the growth conditions produced hardly any effect on flower mass ratio (FMR), and only an increased duration of the LD period had a negative linear effect on the partitioning towards the flowers. The season also had an effect on chrysanthemum FMR: when planted in September (lowest light levels during the SD period), FMR was reduced compared to the other seasons. It is concluded that within a wide range of growth conditions chrysanthemum invests the additional assimilates, diverted to the generative organs, in increasing NoF rather than in increasing flower size. Individual flower size was only affected by assimilate availability when average daily incident photosynthetically active radiation during the SD period was lower than 7.5 mol m sup-2/SUPd sup-1/SUP, resulting in lighter and smaller flowers. When incident photosynthetically active radiation (PAR) during the SD period was higher than this threshold value, a constant flower size was observed for the fully open flowers (0.21 ± 0.10 g plant sup-1/SUPand 25 ± 2 cm sup2/SUPplant sup-1/SUP). Excluding the positive linear effect of the duration of LD period, assimilate availability had no relevant influence on plant height (& lt; 10 % increase). Irrespective of the growth conditions and season, a positive linear relationship between NoF and TDM was observed (NoF = 1.938TDM - 2.34; R sup2 /SUP= 0.90). The parameters of this relationship are cultivar-specific. The generic nature of these results is discussed is this chapter. The functional relationships developed for predicting NoF and flower size were incorporated as 'modules' in a photosynthesis-driven growth model for cut chrysanthemum (Chapter 5.2).