Qian-Qian Su, Yi Chen, Jiao Qin, Tong-Liang Wang, De-Hua Wang and Quan-Sheng Liu

Mifepristone and quinestrol are effective drugs for controlling rodent fertility, but their inhibitory effectiveness during premating, early pregnancy, and late pregnancy is unknown. In this study, six groups of eight female Brandt’s voles (Lasiopodomys brandtii) were administered with mifepristone, quinestrol, or a control for three days during premating, early pregnancy, or late pregnancy. In the mifepristone-treated groups, the premating females bred, whereas the early and late pregnant females did not. The reproductive rate, litter size, average body mass at birth, and survival rate of pups did not significantly differ between the mifepristone-treated premating group and the control group. By contrast, quinestrol treatment completely inhibited fertility during the three reproductive phases. In addition, fertility was not completely restored in the second pairing. The reproductive rates were higher for mifepristone, both during early and late pregnancy, than for quinestrol, but both were lower than the control. Thus, mifepristone and quinestrol both inhibited the fertility of female Brandt’s voles at different reproductive periods. These results suggest that these two sterilants could be delivered during the reproductive season of the target pest animal.

Yin Ling Luo, Zhi Long Su, Xian Liang Cui and Qin Ying Lan

Different plants and plant organs have various strategies to cope with drought stress. Kalanchoe tubiflora plants have a strong ability to prevent water loss and to scavenge reactive oxygen species. The epiphyllous bud of the plant serves as a reproduction unit and is able to generate plantlets even under conditions of extreme drought. The aim of this project was to study the antioxidant-stress response and osmoregulation of K. tubiflora epiphyllous buds to dehydration and to compare the drought-tolerance mechanisms of the plant body and the epiphyllous buds. With the progression of bud dehydration, relative water content, seedling survival rate and dry weight per seedling decreased, and electrolyte leakage, hydrogen peroxide and malondialdehyde content and superoxide anion production rate increased. The activities of the antioxidant enzymes superoxide dismutase, catalase, ascorbate peroxidase, dehydroascorbate reductase and glutathione reductase decreased under dehydration. The content of proline, soluble sugars and soluble protein increased in dehydrated buds proportionally with the extent of water loss. These data indicate that the drought-tolerance mechanism of the K. tubiflora bud was different from that of its mother plant. The buds invest more energy to prevent water loss during drought stress, and their antioxidant defense weakens.