RESUMO
The dynamic simulation of cucumber growth and development in sunlight greenhouse can provide technical support for the intelligent management of cucumber production. According to the cucumber response characteristics to light and temperature, the cucumber development module based on the algorithm of clock model was established by using data from four-stage experiment with 'Jinyou 35' as experiment variety in two years. Based on the relationship between the leaf growth and key meteorological factors (temperature and radiation), leaf area index (LAI) module was established with the accumulated product of thermal effectiveness and photosynthetically active radiation (TEP) as independent variables. The simulation module of cucumber dry matter production was established by taking into consideration the double integral of LAI and daily length in photosynthesis per unit leaf area as well as the respiratory expenditure of different organs. Combined with water content of organs, fresh weight simulation module of cucumber organs was constructed. The whole cucumber development and growth simulation model in greenhouse was built based on each sub-module. The model parameters were calibrated and determined. The results showed that root mean square error (RMSE) of simulated values and observed values of four deve-lopment stages (from transplanting date to stretch tendril, to initial flowering, to early harvested and to uprooting), was 3.9-10.5 d. The normalized root mean square error (nRMSE) was 6.5%-28.6%. The coincidence index (D) was 0.79-0.97. The relationship between LAI and TEP was the regression of 'S' type curve. The RMSE of simulated and observed LAI values was 0.19. The nRMSE was 17.2%. The D value was 0.90. The RMSE of dry weight of root, stem, leaf, flower and fruit of the simulated values and observed values were 0.39-8.94 g·m-2. The nRMSE were 10.9%-17.7%. The D values were all above 0.98. The growth and development model of cucumber could accurately simulate the key development period of cucumber, leaf area and the dry and fresh weight of various organs and quantify the growth and development of cucumber in sunlight greenhouse.
Assuntos
Cucumis sativus , Crescimento e Desenvolvimento , Fotossíntese , Folhas de Planta , Luz SolarRESUMO
OBJECTIVE: To observe the effect difference of electroacupuncture (EA) stimulation of Shenmen (HT 7) and Taiyuan (LU 9) on P 300 of event-related potentials (ERPs) in volunteer subjects, so as to explore functional specificity of acupoints in processing cerebral information. METHODS: Sixty healthy volunteer college students were randomly and equally divided into Shenmen (HT 7) group and Taiyuan (LU 9) group (30 persons/group). EA (2 Hz, 1 mA) was applied to bilateral Shenmen (HT 7) and Taiyuan (LU 9) for 15 min. The ERPs were acquired by averaging EEG activity following Oddba II auditory tone-double stimuli and brain electrical activity mapping (BEAM) acquired by means of Scan 4.5 collection and analysis system. Data were calculated and analyzed with SPSS 17.0 for Windows. After testing, the subjects were inquired about the perception for acupuncture stimulation and other sensations or psychological activities. RESULTS: Following EA stimulation of both HT 7 and LU 9, the amplitude of P 300 in the ERPs were significantly decreased in comparison with pre-EA stimulation in the same one group (P < 0.01, P < 0.05). No significant changes were found in the latencies of P 300 after EA stimulation of both HT 7 and LU 9 (P > 0.05). But, EA of HT 7 had a slightly stronger effect in shortening P 300 latency. With regard to the potential intensity distribution of BEAM, there were some differences between HT 7 and LU 9 groups. The high potential responses for HT 7 were found mainly in the occipital lobe, and in the left parietal lobe and the right temporal lobe, whereas those for LU 9 were found to mainly disperse in the left occipital lobe and the parietal lobe. CONCLUSION: EA stimulation of HT 7 and LU 9 has a slight difference on lowering P 300 amplitude of ERPs, and may result in different distribution of the high potential responses in different lobes of the cerebral cortex in healthy subjects. The functional specificity of EA stimulation of different acupoints needs further study.