| Poinsettia {Euphorbia pulcherrima Willd.) is one of the main greenhouse potted flowers in the world and the most popular Spring Festival flowers in China. Standardization of environment control and cultivation management can be sure to give the market high quality products. Since the history of Chinese commercial poinsettia production is short and the basic physiological and ecological research is weak, Chinese mainly use foreign experiences as reference in there cultivation management of poinsettia. But there are big differences between China and other countries in climate, greenhouse establishment and economy condition, so the foreign experiences don't work well, which lead our poinsettia quality decreasing. Aiming at these problems in poinsettia production, through different planting date and different pruning methods experiments, the quantitive relationship of light, temperature and cultivation methods on growth, development and quality of poinsettia were studied for guideline for the optimization of temperature and radiation control for poinsettia production in greenhouse.(1) Leaf area model: as potted flower, poinsettia quality standard indices such as canopy diameter, the ratio of canopy diameter to plant height, plant chubbiness, total impression have relationships to leaf area, so leaf affects not only plant growth, but also the quality. Measuring leaf area is important to the study of biological characteristics, guidelines for production and quality evaluation for poinsettia. According to observed data the leaf area model(LA) based on leaf length(LL) and leaf width(LW) was built in this study: LA=0.6826x(LLxLW), R2=0.960, SE=3.899 mm2 . Using independent datum to validate the formulation proved the leaf area regressing model can predict leaf area of poinsettia accurately. Leaf area model based on leaf length and leaf width can quickly tell poinsettia leaf area undamaged .(2) The quantitive relations between photothermal product and poinsettia development and quality: according to effects of solar radiation, temperature on poinsettia development and quality, the integrated light and temperature index-Photothermal Product(PTP) was put forward for the first time. PTP is the product of relative thermal effectiveness and photosynthetically active radiation.PTP is calculated by formulae as follows:Te is the effective temperature; Tb, To, Tc are the base, optimum and ceiling temperatures for poinsettia development; RTE is the relative thermal effectiveness; PAR is photosynthetically active radiation (MJ·m-2·d-1) ; PTPi is the PTP for day i; PTP is the accumulated PTP for some stage. 4 different planting dates experiments were conducted and the results show that the required PTP are 86.7±10.7, 127.1±6.0,145.1±9.3, 197.8±11.0 MJ·m-2, respectively, for development stage from the starting short-day to Single-bract, Single-bud, Multi-bud and Anthesis. The net increment of the number of leaves on main stem (MLN ) , the number of leaves per branch (BLN ) and the number of bracts per branch (BN) are linearly related to PTP (MLN =0.0352×PTP, R2 =0.915, SE=0.772; BLN = 0.042044×PTP, R2=0.9162, SE=0.6822; BN = 0.0864×PTP - 6.7807, R2 = 0.933, SE=0.8589).The relation between the ratio of net plant height increment to seedling leaf area (HLR) and PTP follows power function (HLR =0.0030x PTP1.616, R2 = 0.9, SE= 1.6475 mm·dm-2) and the ratio of canopy diameter to plant height (PDH) and PTP follows negative exponent function (PDH=1.25×(l-EXP(-0.023xPTP/1.25)), R2 - 0.8458, SE=0.0979) . These results can be used as the guideline for the optimization of temperature and radiation control for poinsettia production in greenhouse.(3) Effect of pruning methods on external quality of poinsettia: Chinese poinsettia production is different to foreign' because they mainly harvest poinsetta for Spring Festival. Commonly they begin poinsettia production from August, grow them in autumn and winter when radiation is weak and temperature is low, which lead low quality for poinsettia. Pruning is one of the most effective cultivation...
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