Parvalbumin positive interneurons are selectively altered in number and function in rat hippocampus after chronic low dose exposure to MK 801

Abstract

A simple method for pollen collection and storage was devised for three litchi cultivars, namely, ‘Sanyuehong,’ ‘Shuidong,’ and ‘Guiwei’. This method could realize long-term pollen storage over periods of up to two years for artificial pollination and crossbreeding. The most suitable drying method for litchi pollen was the use of an air-blowing electric dryer at 35 °C for 6 h. The germination rate of pollen stored at different temperatures (30 °C, 25 °C, 15 °C, 4 °C, and −86 °C) was investigated. The pollen germination rate decreased to lower than 5% after 9, 16, 27, and 52 d at 30 °C, 25 °C, 15 °C, and 4 °C, respectively. A significant negative correlation was observed between pollen germination rate and storage time. For all litchi cultivars tested, pollen cryo-stored (−86 °C) for one year showed significantly higher germination rates than those stored under the other conditions. Pollen stored at −86 °C maintained a high germination rate of above 70% even after two years of storage. Thus, our results indicated that storage of pollen at 4 °C was suitable for field pollinations in the blooming season for up to two months. However, storage at −86 °C maintained the high germination rates required for artificial hybridization even in the second year of storage.