[Effects of high temperature on photosynthetic physiological characteristics of strawberry seedlings in greenhouse and construction of stress level.] / é«˜æ¸©å¯¹æ¸©å®¤è‰èŽ“å ‰åˆç”Ÿç†ç‰¹æ€§çš„å½±å“åŠèƒè¿«ç­‰çº§æž„å»º.

Strawberry variety 'Benihoppe' was used as the experimental material. The temperature treatments were set at 32 ℃/22 ℃, 35 ℃/25 ℃, 38 ℃/28 ℃ and 41 ℃/31 ℃ (daily maximum temperature/daily minimum temperature), and the stress days lasted for 2, 5, 8 and 11 d, with 28 ℃/18 ℃ as the control. We measured the photosynthetic characteristics, chlorophyll fluorescence characteristics, reactive oxygen species, protective enzyme activity and membrane lipid peroxidation of strawberry under different high temperature treatments. The key indices were extracted by principal component analysis. The high temperature stress index (Z) was defined to divide the high temperature stress grade. The results showed that 1) with the aggravation of high temperature stress and the extension of stress time, chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoid (Car), light saturation point (LSP), maximum net photosynthetic rate (Pmax), apparent quantum efficiency (AQE) and maximum photochemical efficiency (Fv/Fm) decreased, while light compensation point (LCP) and dark respiration rate (Rd) increased. 2) High temperature hindered the energy transfer of thylakoid in PSⅡ center (ΔWOK＞0), and accelerated the reduction rate of PSⅠ terminal electron receptor pool. On the 11th day of the stress, except that under 32 ℃, all other oxygen evolution complexes (OEC) were inactivated. 3) The content of reactive oxygen species (H2O2 Content and O2-· production rate) and malondialdehyde (MDA) increased with the stress days under different high temperature treatments. 4) The protective enzyme activities and soluble protein content increased first and then decreased with stress duration. 5) Based on principal component analysis (PCA) and combined with the difficulty of index acquisition, Chl a, Pmax, Fv/Fm and MDA were extracted as the key indices, and Z value was calculated. Five high temperature stress grades were divided which were normal (0

[Climate suitability for tea growing in Zhejiang Province].

It is important to quantitatively assess the climate suitability of tea and its response to climate change. Based on meteorological indices of tea growth and daily meteorological data from 1971 to 2010 in Zhejiang Province, three climate suitability models for single climate factors, including temperature, precipitation and sunshine, were established at a 10-day scale by using the fuzzy mathematics method, and a comprehensive climate suitability model was established with the geometric average method. The results indicated that the climate suitability was high in the tea growth season in Zhejiang Province, and the three kinds of climate suitability were all higher than 0.6. As for the single factor climate suitability, temperature suitability was the highest and sunshine suitability was the lowest. There were obvious inter-annual variations of tea climate suitability, with a decline trend in the 1970s, less variation in the 1980s, and an obvious incline trend after the 1990s. The change tendency of climate suitability for spring tea was similar with that of annual climate suitability, lower in the 1980s, higher in the 1970s and after the 1990s. However, the variation amplitude of the climate suitability for spring tea was larger. The climate suitability for summer tea and autumn tea showed a decline trend from 1971 to 2010.

[Effects of stem numbers per ground area on the quality of standard cut Chrysanthemum morifolium in greenhouse: simulation model].

In order to understand the effects of stem numbers per ground area on the quality of standard cut Chrysanthemum morifolium, an experiment with different cultivars, different stem numbers per plant, different planting densities, and different planting dates was conducted in a greenhouse in Shanghai in 2005 and 2006. The effects of stem numbers per ground area on the canopy leaf area index and external quality of standard cut C. morifolium were quantified using the experimental data. Based on the physiological product of thermal effectiveness and PAR (PETP) the canopy absorbed, a model for predicting the effects of stem numbers per ground area on the quality of standard cut C. morifolium was developed, and validated with independent experimental data. The results showed that with the increase of stem numbers per ground area, the leaf area index increased, whereas plant height, stem diameter, leaf number, and flower diameter decreased. The model gave satisfactory predictions of the quality of standard cut C. morifolium cultivated with different stem numbers and planting density. The coefficient of determination (R2) and relative prediction error (RSE) based on the 1:1 line for fresh mass per stem, plant height, stem diameter, leaf number, flower diameter, and the number of qualified stem harvested per ground area were 0.95, 0.96, 0.94, 0.91, 0.81 and 0.97, and 16.1%, 10.1%, 12.8%, 13.4%, 15.9%, 16.1% , respectively. The model developed in this study could be used for the optimization of light and temperature management for standard cut C. morifolium cultivated with different stem numbers and planting densities in greenhouse.

[Quality prediction model of greenhouse standard cut chrysanthemum based on light-temperature effect].

Based on the effects of light and temperature on chrysanthemum quality and the experiments with different chrysanthemum varieties and planting dates, a quality prediction model of greenhouse standard cut chrysanthemum with the physiological product of thermal effectiveness and PAR (PTEP) as the measurement scale was developed and validated. The results showed that the predicted results, including the number of unfolding leaves, leaf area, plant height, stem diameter, internode length and flower diameter, accorded well with the observed ones, and the determination coefficient (R2) and relative prediction error (RSE) based on 1 : 1 line were 0.99, 0.98, 0.98, 0.92, 0.87 and 0.88, and 5.5%, 6.5%, 5.9%, 4.1%, 11.2%, 12.4%, respectively. This model was of high precision and practicable, which could be used in optimizing the light and temperature management for greenhouse standard cut chrysanthemum production.