克鲁兹王莲(睡莲科)的开花生物学研究

Floral Biology of Victoria cruziana(Nymphaeaceae)

分别于2003和2004年8月在北京地区观察了户外种植的克鲁兹王莲（Victoria cruziana）花的生物学。结果显示：（1）克鲁兹王莲的花在连续2d内开放和关闭，第1天花开放的时间为19：20；第2天于12：00～13：00完成关闭过程，第2天15：00～16：00花第2次开放，第3天早晨花关闭后沉入水下。（2）开花第1天晚上花内温度高出环境温度最高达11℃，开花的第2天以后，花内温度与水表面温度相近。（3）克鲁兹王莲的花第1次和第2次开放以及关闭过程中花器官呈现有规律的运动，第1天晚上花的开放过程可划分为4个时期，花的第1次关闭与第1次开放过程中花器官的运动不是简单的相反过程，第2次开放与第1次开放的过程也不相同。（4）首次描述了拟雄蕊、雄蕊以及伴生心皮（paracarpels）在开花和关闭过程中的活动规律；开花第1天晚上的柱头是湿润的，但并不像睡莲属（Nymphaea）植物那样积累1池粘液。（5）在北京地区，克鲁兹王莲自花受精能够产生种子。研究结果认为王莲属植物的花具有很多高度特化的特征以适应昆虫传粉。

Our studies conducted in August 2003 and 2004 of the floral biology of Victoria cruziana grown in an outdoor pool in Beijing indicate that the flowers open and close on two successive days. The flowers open at 19：20 on the first day,begin to close in the following morning and become completely closed between 12：00 and 13：00. The flowers re-open between 15..00 and 16.00 on the same day. When the flowers have closed for the second time on the third day, they are gradually pulled under water. We recorded a maximum temperature difference of 11 ℃ between the environment and the flower interior when the flowers were opening for the first time in the evening. On the second day of flower opening the temperature of flowers approached that of water surface. Here we report for the first time the regular movements of floral organs during the first and second opening and closing. The unfolding process of flowers on the first day can be divided into four stages. The process of the first closing is not simply the reverse of that of the first opening. The process of the first opening also differs from that of the second opening. We further describe here for the first time the regular movements of staminodes, stamens and paracarpels during the opening and closing of the flower. The stigma is wet on the first day of opening but without the accumulation of a secreted pool of stigma fluid as is the case in the genus Nyrnphaea. The flowers,if self-pollinated,produce seeds in Beijing area. Based on our studies on V. cruziana,it is suggested that the flowers of Victoria are highly specialized and adapted for pollination by insects.