Studies on the relationship between bud size and microspore periods in squash | 西葫芦花蕾纵横径长度与小孢子发育关系研究

Chinese. 研究西葫芦小孢子发育时期与花蕾纵径长度、横径长度和纵横径比之间的关系，找到一种能够快速准确判断小孢子发育时期的方法。以“春玉2号”为试材，采集第3位次雄花花蕾，测量其纵径、横径长度，计算纵横径比，观察对应的花蕾小孢子发育时期，寻找它们之间的相关性；同时观察不同位次上雄花小孢子的发育时期，比较各位次在小孢子相同发育时期花蕾纵径和横径长度的差异性。花蕾纵径长度和横径长度在四分体时期为0.95～1.05 cm和0.48～0.52 cm，在单核早期为1.06～1.15 cm和0.53～0.55 cm，在单核中后期为1.16～1.25 cm 和0.56～0.59 cm，在双核期为1.26～1.35 cm和0.60～0.63 cm，小孢子各发育时期间花蕾纵横径长度均存在显著差异；“春玉2号”前7个位次上雄花小孢子相同发育时期的花蕾纵径长度或横径长度之间最大差值均为0.04 cm，位次间差异不显著。“春玉2号”小孢子处于单核靠边期时，小孢子细胞膜和细胞壁加厚，细胞中出现大液泡，细胞核被挤到细胞的一侧，靠近细胞壁；小孢子发育时期与花蕾纵径长度或横径长度存在相关性，植株前7个位次上任何一朵雄花花蕾的纵径长度或横径长度均可作为判断小孢子发育时期的依据。

English. Research on the relationship between the squash microspore development and the morphological characteristics of the buds was done to find a method to confirm the microspore develop period quickly and accurately. Using the Chunyu 2 squash as experimental material, the third buds of the male flower were collected, the length and diameter surveyed, the ratio of length to diameter calculated, and the development periods of the microspores observed to find out the relationship between them. The periods of the buds in different turns were observed to find out the differences of the lengths and the diameters in different turns. The result showed that, while the peak stage of tetrad, early-uninucleate, late-uninucleate and binucleate of pollens appeared when the bud lengths were between 0.95-1.05 cm, 1.06-1.15 cm, 1.16-1.25 cm, 1.26-1.35 cm, and the breadths were between 0.48-0.52 cm, 0.53-0.55 cm, 0.56-0.59 cm, 0.60-0.63 cm. There were both significant differences between the lengths or the diameters in different periods. The maximum differences of the lengths or the diameters in the same period were both 0.04. There were no significant differences between the buds at different turns. When the microspore period of the Chunyu 2 squash was in late-uninucleate, the cell membrane and the cell wall got thicker, and large vacuoles appeared in the cells, the nucleus was packed to one side of the cell, close to the cell wall; there was relationship between the microspore periods and bud length or diameter. The length or the diameter of any bud at the first 7 turns can be used as a basis to judge the microspore periods.