<正>将经过干旱（基质含水率低于6.0%）72h、低温（（10±1）℃）7211、盐（0.25mol/LNaCl溶液）120h预处理的3组麻疯树（JatrophacurcasL.）幼苗。与对照组一起置于低温（（2±1）℃）条件下72h。测定其间叶片的电解质相对渗漏率和叶鲜重等的变化。结果表明：与对照相比。经预处理的幼苗在2℃左右低温下除生长状况较好外。叶片电解质相对渗漏率显著降低。叶鲜重受影响较小。换言之，不同胁迫预处理能有效地提高麻疯树幼苗的抗冷性，说明麻疯树幼苗具有一定的交叉适应能力。

O-similar and O-congruent matrices, and their properties and the O-similar and O-congruent equivalent conditions were defined. Some consequences of the full-transposed, symmetric, sub-symmetric and adjoint matrices were given. As for application, a way of finding sub-diagonalization and O-orthogonal matrices was given.