Studies On Effects Of Different Temperature And Light On The Pollen Viability And Seed-setting Rate In Pepper (Capsicum. Annuum L.)

Pepper (Capsicum annuum L.) is one of the most important vegetable crops . Although it has some tolerance to the ambient environment, its pollen viability and seed set are greatly affected by it. High temperature together with high light intensity which often happens in summer and early autumn, and low temperature together with low light intensity which occurs in early spring and late autumn always lead to flower bud drop, flower drop, abscission of fruits and so on. There is an emergent necessity to deal with these problems. In this experiment, three traditional varieties ( Xiangtanwan, 7801 and Hexiniujiaojiao) were selected as test materials. Their pollen viability and seed set in different light intensity and different temperature were measured and the correlations of seed-setting rate with pollen viability were analyzed. The result showed:1. Effects of four testing methods to detect the pollen viability of pepper were being compared. The results indicated that two testing methods of staining with I-KI and TTC were not suitable to judge the pollen viability of pepper. By and large, the hanging drop culture method was an efficient, stable and simple way to judge the pollen viability of pepper.2. The progress of pollen development and meiosis of three species were observed, and this test attempted to use length of flower bud to measure the pollen development. The results indicated that the length of flower bud was correlation with pollen development as for the same species. When it comes to different species, though there are obvious difference in flower bud between different varieties, there are also regularities existed: When the flower bud is longer than 5 millimeter, the microspore development is the predominant stage. When the length of flower bud is between 1 millimeter to 5 millimeter, the meiosis stage is the predominant stage. While flower bud is shorter than 1 millimeter, the pollen development is mainly before meiosis stage.3. The present experiments, using hair-drier to imitate hot-dry wind , founded that the sensitive stage to ambient environment in the development of pepper pollenwere from telophase I to telophase II.4.Through man-made controlled condition in climate chambers, the results indicated that there was significant correlation existed between pollen viability and seed-setting rate under high temperature, while there was no significant correlation under low temperature. It proved that the pollen viability is one of the most important indexes to appraise the hot-tolerance in different pepper species. But it was not the critic indexes in appraising the cold-tolerance.5. By shading methods to imitate low intensity and the natural high light intensity in summer , it comes to the conclusion that pollen viability is one of the most efficient high light intensity tolerance indexes. But it is also not the critic indexes in appraising the low light intensity tolerance.