关键词: 茎流速率, 东北春玉米, 光合参数, 根叶水势, 干旱胁迫

Abstract: Egg masses of Pomacea canaliculata were collected monthly from three habitats including reservoir, rice field, and irrigation canals and ditches in Ya’an, Sichuan Province from March to October 2012 and the fecundity of P. canaliculata was studied by using the methods of collecting snail eggs in the fields and breeding in the laboratory. The field investigation results indicated that egg numbers per egg mass varied distinctly, ranging from 33 to 621 individual eggs per mass (an average of 233 individual eggs per mass) with a coefficient of variation (CV) of 55.0%. The egg diameter ranged from 2.17 to 3.20 mm (mean = 2.60 mm, CV = 8.95%). The number of eggs was significantly positively correlated with the weight of egg mass (P<0.01). The absolute fecundity value of P. canaliculata in May was the highest (403.1 eggs·mass^-1), and significantly different (P<0.05) from those in the other months. The absolute fecundity from the reservoir was higher (P<0.05) than from rice field and irrigation canals and ditches. Meanwhile, a comparative study on the fecundity of P. canaliculata collected from Chengdu, Ya’an and Ziyang was also conducted by using the singlepair mating method in the laboratory. The results showed that the individual relative fecundity values from the three areas were 12.33, 9.58 and 10.54 eggs per gram of snail body weight, and 4.55, 3.92 and 3.54 eggs per millimeter of the snial shell height, respectively. The individual relative fecundity values of P. canaliculata from the three areas were not significantly different. Our work would provide a preliminary understanding for the reproductive characteristics of P. canaliculata in Sichuan and offer a scientific reference for snail prevention and control.

Key words: stem flow rate, spring maize in Northeast China, root and leaf water potentials, photosynthetic parameter, drought stress