<正>为了探讨松萎蔫病与松材线虫的关系，笔者研制了一种简单试验装置“冷闸”，使接种的线虫被隔离在松树接种枝内而不能迁移。用该装置进行接种试验的结果表明：在松材线虫被局限于接种枝内而不能移动到寄主其他部位的情况下，接种无菌松材线虫与致病荧光假单胞菌Pseudomonas fluorescens GcM5-1A，以及该致病细菌体外培养的无细胞滤液，同样能诱发该病。该致病细菌又从接种无菌线虫和致病细菌后病死寄主中分离到并被鉴定，证明符合柯赫法则。致病荧光假单胞菌GcM5-1A体外培养的无细胞滤液接种试验结果说明，该致病菌株培养物中的内吸性毒素导致了寄主的萎蔫和死亡。由此，松萎蔫病经实验证实为首例由细菌和线虫互惠共生复合体引起的植物病害。

Based on the structure characteristic of plywood and former predictions of in-plane modulus of poplar veneer, the stiffness models of classical laminate plate theory were applied to plywood. In the models test, two plies impregnated paper were orthotropicly overlaided on the face and back poplar veneer. When the test specimens were under single axial tensile load or pure bending moment load, the strain of face and back plies, ε x and ε y was obtained through strain gage. The experimental and theoretic value of some compliance coefficients were tested. The results showed that the stiffness models could predict the stiffness of plywood well, and the stiffness models of classical laminate plate theory could be used to describe the stiffness of plywood.