Analysis of the strength properties of pea stems
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Institute of Agrophysics Polish Academy of Sciences, Doświadczalna 4, P.O. Box 201, 20-290 Lublin 27, Poland
Botanical Institute, Russian Academy of Sciences, Prof. Popova 2, St. Petersburg, 197376 Russia
Agrophysical Research Institute, 14 Grazhdansky Prospekt, St. Petersburg, 195220 Russia
Int. Agrophys. 2007, 21(2): 189–197
In the study the authors determined the mechanical properties of pea stems, in the dynamic test, as well as the wall thickness of hollow stem (G) and cross-section area (S). The study was conducted on narrow-leaf pea varieties with varied resistance to lodging: Komandor (susceptible to lodging) and Brutus (resistant to lodging). For purposes of result comparison, also an older lodging-resistant variety - Piast - was included in the study. The strength characteristics of pea stems were obtained through determination of cutting work (Ed) and cutting work per unit of stem cross-section area (wd), with the help of Dynstat apparatus. The measurements were taken at five points on the stem height. It was demonstrated that the cutting work reaches the highest value in the middle of stem length, while the work per unit of stem cross-section area is the highest close to the root. The study showed that there is a differentiation of the mechanical properties of pea stems. Varieties resistant to lodging are characterized by much higher values of their mechanical parameters. On the basis of correlation coefficients a significant correlation was found between the cutting work and the stem wall thickness and cross-section surface area. Negative correlation coefficients were obtained for the correlation between the cutting work per unit of stem cross-section area and the geometrical parameters of the stems. On the basis of the cutting work and the cutting work per unit of stem cross-section area intervarietal differences were shown. At the same time, the study in which estimation was made of the absorption of X-ray radiation by stems on the basis of the parameter DOD, determined with the densitometric method, showed intervarietal differences. Complementary anatomical study, made on the basis of seven traits, showed cross-sections at the analysed heights on the stems of pea varieties, suggesting also the occurrence of intervarietal differences.