Measurement of Static Lateral Stability Angle and Roll Moment of Inertia for Agricultural Tractors with Attached Implements.

Each year, many fatalities result from rollovers of agricultural tractors in Japan. In addition to rollover protective structures (ROPS) and seat belts, a warning device that alerts the operator of impending rollover based on the tractor stability index is a measure used to prevent rollovers. The stability index requires inertial parameters, which have been measured only for the single body of the tractor, to calculate the warning threshold. In this study, the center of gravity (CoG) and lateral stability angles of three agricultural tractors were measured, and lateral stability angles were also calculated and compared with measured values for three tractor-tiller combinations to analyze the effect of the attached implement on the tractor stability as well as to verify the accuracy of the calculation methods. The roll moment of inertia (RMI) was also measured for two tractors and two rotary tillers, and RMI values for tractor-tiller combinations were calculated. The measurement and calculation results show that the attached implement increased the lateral stability angle of tractors in phase I rollover and decreased the lateral stability angle in phase II rollover, and for a certain tractor-tiller combination, there was no transition from phase I to phase II rollover. The difference between the measured and calculated lateral stability angles in phase I ranged from -3.5° to 2.5°, while that in phase II ranged from 0.2° to 5.2°. The RMI about the longitudinal axis through the CoG was 203 and 433 kg m-2 for tractors A and B, respectively, and 52 and 94 kg m-2 for rotary tillers D and F, respectively. The calculated RMI values were 265 and 540 kg m-2 for tractor-tiller combinations A-D and B-E, respectively.

Overexpression of a rice heme activator protein gene (OsHAP2E) confers resistance to pathogens, salinity and drought, and increases photosynthesis and tiller number.

Heme activator protein (HAP), also known as nuclear factor Y or CCAAT binding factor (HAP/NF-Y/CBF), has important functions in regulating plant growth, development and stress responses. The expression of rice HAP gene (OsHAP2E) was induced by probenazole (PBZ), a chemical inducer of disease resistance. To characterize the gene, the chimeric gene (OsHAP2E::GUS) engineered to carry the structural gene encoding ß-glucuronidase (GUS) driven by the promoter from OsHAP2E was introduced into rice. The transgenic lines of OsHAP2Ein::GUS with the intron showed high GUS activity in the wounds and surrounding tissues. When treated by salicylic acid (SA), isonicotinic acid (INA), abscisic acid (ABA) and hydrogen peroxide (H2 O2 ), the lines showed GUS activity exclusively in vascular tissues and mesophyll cells. This activity was enhanced after inoculation with Magnaporthe oryzae or Xanthomonas oryzae pv. oryzae. The OsHAP2E expression level was also induced after inoculation of rice with M. oryzae and X. oryzae pv. oryzae and after treatment with SA, INA, ABA and H2 O2, respectively. We further produced transgenic rice overexpressing OsHAP2E. These lines conferred resistance to M. oryzae or X. oryzae pv. oryzae and to salinity and drought. Furthermore, they showed a higher photosynthetic rate and an increased number of tillers. Microarray analysis showed up-regulation of defence-related genes. These results suggest that this gene could contribute to conferring biotic and abiotic resistances and increasing photosynthesis and tiller numbers.