[Effects of NaCl stress on polyamines metabolism in vegetable soybean].

By adopting vermiculite culture, this paper studied the malondialdehyde (MDA) content and polyamines (PAs) metabolism in the seeds of two vegetable soybean cultivars with different salt tolerance under the stress of 100 mmol NaCl x L(-1). NaCl stress increased the MDA contents in the seeds of the two cultivars significantly, but the increment was lower for salt-resistant cultivar 'Lülingtezao' (LL) than for salt-sensitive cultivar 'Lixianggaochan 95-1' (LX). In the whole period of NaCl stress, LL seeds had higher contents of free spermine (Spm), conjugated Spm, conjugated spermidine (Spd), bound Spd and bound putrescine (Put), higher values of (Spd+Spm)/Put and (cPAs+bPAs)/fPAs, and lower value of Put/PAs, and had higher content of free Spd in the mid and late period (9-15 d) of NaCl stress, as compared with LX seeds. In a longer term (6-15 d) of the stress, LL seeds maintained a higher activity of arginine decarboxylase (ADC) and a lower activity of polyamine oxidase (PAO). All the results suggested that LL seeds had stronger capabilities for polyamines synthesis and for the transformation of Put to Spd and Spm and of free polyamine to conjugated and bound polyamines, which effectively inhibited the membrane lipid peroxidation, possibly being one of the important reasons for the stronger salt tolerance of LL.

[Change characteristics of climate and water resources in west Liaohe River Plain].

Based on the 1951-2007 observation data of precipitation and temperature from Tongliao, Kailu, and Zhalute meteorological stations as well as the related hydrologic data from Tongliao hydrological survey bureau and water affairs bureau, the change characteristics of the climate and water resources in west Liaohe River Plain were studied. The results showed that in 1951-2007, the precipitation in its periodical changes in study area had a decreasing trend. The tendency rate of precipitation was -13.2 mm x (10 a)(-1), and the instability of precipitation was increased. The runoff of four inbound rivers including Xilamulun all decreased, with the mean annual runoff in 2001-2007 being only 22.8% of that in 1990-1994. From 1951 to 2007, the runoff of west Liaohe River decreased, and the days of its zero flow increased. Since 2001, the River had been zero flow. The groundwater overdraft area and the funnel area in Keerqin Region in 2006 increased by 8.5 times and 15.5 times, respectively, compared with those in 1978; and the average groundwater level in Keerqin Region, Kailu County, and Naiman Banner in 2006 increased by 3.76 m, 2.77 m, and 1.93 m, respectively, compared with that in 1980. Since the 1970s, the number of electromechanical well in study area was increasing, irrigation amount had a fluctuated rise, and the proportion of agricultural water consumption had different extent decrease. Therefore, to exploit and use the water resources in atmosphere, to popularize water-saving irrigation technologies, and to make a reasonable arrangement of industrial structure were the effective measures in realizing the sustainable utilization of water resources in west Liaohe River Plain.