使用扫描电子显微镜(SEM)观察了路易斯安那鸢尾(Louisiana Iris)品种‘梦娣达’(‘Mentida’)和红籽鸢尾(Iris foetidissima Linn.)的花粉形状、外壁纹饰和大小;同时,以路易斯安那鸢尾为母本、红籽鸢尾为父本进行杂交和路易斯安那鸢尾自交,分析了杂交和自交授粉后花粉管生长状况及雌蕊中保护酶(包括SOD 和POD)活性和内源激素(包括IAA、GA3 、ZR 和ABA)含量的动态变化。结果表明:路易斯安那鸢尾花粉粒近扁球形,外壁纹饰为细网状,极轴和赤道轴长度分别为81. 71 和58. 00 μm;红籽鸢尾花粉粒近长球形,外壁纹饰为显著粗网状,极轴和赤道轴长度分别为91. 80 和38. 23 μm,表明二者的花粉形态差异明显。与自交组相比,杂交组的花粉萌发和花粉管生长相对滞后,授粉后48 h 仅有少量花粉管到达花柱基部,且伴有花粉管末端弯曲及在柱头表面回转、盘结等现象。在授粉后2 h 内自交组雌蕊的SOD 和POD 活性和IAA 含量均高于杂交组;授粉后8 ~12 h 自交组雌蕊的IAA 含量低于杂交组;授粉后12 ~24 h 自交组雌蕊的GA3 和ZR 含量均低于杂交组;授粉后多数时段自交组雌蕊的ABA 含量低于杂交组。说明雌蕊中的高水平SOD 和POD 活性以及IAA 含量和低水平ABA 含量有利于柱头识别花粉及花粉萌发,而雌蕊中的低水平IAA、GA3 和ZR 含量则有利于花粉管的生长。综合分析结果表明:路易斯安那鸢尾和红籽鸢尾种间杂交存在一定程度的受精前障碍,可能是导致其种间杂交不亲和的原因之一。

Shape, extine ornamentation and size of pollens of Louisiana Iris ‘ Mentida’ and Iris foetidissima Linn. were observed by scanning electron microscope ( SEM), meanwhile, interspecific hybridization using Louisiana Iris as female parent and I. foetidissima as male parent and self pollination of Louisiana Iris were carried out, and pollen tube growth status and dynamic changes of protective enzyme (including SOD and POD) activity and endogenous hormone (including IAA, GA3, ZR and ABA) content in pistil after hybrid and self pollinations were analyzed. The results show that pollen grain of Louisiana Iris is suboblate with fine reticulate extine ornamentation, lengths of its polar and equatorial axes are 81. 71 and 58. 00 μm, respectively; pollen grain of I. foetidissima is subprolate with obviously rough reticulate extine ornamentation, lengths of its polar and equatorial axes are 91. 80 and 38. 23 μm, respectively, indicating that there are obvious differences between their pollen morphology. Compared to self group, pollen germination and pollen tube growth of hybrid group are relatively backward, and only a few pollen tubes reach the base of style. after pollination 48 h and accompany with phenomena of terminal bending, rotating and wind round in stigma surface, etc. After pollination in 2 h, SOD and POD activities and IAA content in pistil of self group all are higher than those of hybrid group; after pollination 8-12 h, IAA content in pistil of self group is lower than that of hybrid group; after pollination 12-24 h, both GA3 and ZR contents in pistil of self group are lower than those of hybrid group; and at most times after pollination, ABA content in pistil of self group is lower than that of hybrid group. It is meant that high level of SOD and POD activities and IAA content, low level of ABA content in pistil are beneficial to stigma to recognize pollen and pollen germination, while low level of IAA, GA3 and ZR contents in pistil favors growth of pollen tube. The omprehensive analysis result indicates that there is pre-fertilization barrier at a certain degree in interspecific hybrid of Louisiana Iris and I. foetidissima, it might be one of reasons leading to their interspecific hybrid incompatibility.