棱角丝瓜不同品种对霜霉病抗性的相关研究

Studies on the Resistance of Different Cultivars of Ridgegourd to Downy Mildew

用不同抗性的丝瓜品种为材料，通过对气孔、糖含量、过氧化物酶、多酚氧化酶等多项指标的测定，结果表明：丝瓜叶片中多酚氧化酶活性、还原性糖／可溶性总糖比值、叶下表皮气孔密度与丝瓜对霜霉病的抗性呈负相关，其相关系数分别为-0．9861、-0．7165、-0．9692；而可溶性总糖含量与抗病性呈正相关（r=0．9115）；与还原性糖含量及过氧化物酶活性无关，气孔大小与抗病性无关．

After testing some factors such as stomata, sugar content and the activities of peroxidase(POD) polyphenoloxidase (PPO) etc. from vary ridgegourd (Luffa acutangula ) varities with differenthardiness, the results showed that in leaves of ridgegourd, the PPO ratio of reducing sugar content to totalsugar content and the stomata density of its lower epidermis were negatively relevant to its resistance a-gainst downy mildew (Pseudopronospora cubensis ). The corelation coefficients were 0. 986 1, - 0. 716 5and - 0.969 2 respectively, while the total sugar content were positively relevant to its resistance (r =0. 911 5 ). However POD activity, reducing sugar content and stomata size were all irrelevant to the resis-tance.