[Objective] This study aimed to explore an optimum application amount of nitrogen for cotton cultivation. [Method] In this study, a field experiment was conducted to investigate the effects of nitrogen application amount on the growth characteristics, boll development and lint yield of high quality cotton line FZ-1. [Result] Compared with the nitrogen level of 225 kg/hm2, the lint yield had increased by 28.46% and 18.73%, respectively, with the nitrogen application amount of 300 and 375 kg/hm2. When the nitrogen application amount had increased from 225 to 300 kg/hm2, boll number per plant, boll weight and lint yield had significantly increased. At the nitrogen level of 375 kg/hm2, however, the effects of increasing lint yield were significantly less than that at the nitrogen level of 300 kg/hm2. Compared with the nitrogen levels of 225 and 375, 300 kg/hm2 of nitrogen was the optimum application amount to improve the plant height, daily increment of plant height, number of fruit branches, number ratio of nodes to fruit branches, boll volume and seed cotton weight per boll. [Conclusion] The rational management of nitrogen is the most effective way to promote the growth and development of cotton plants, ensure high yielding ability and minimize the environmental pollution caused by the overuse of nitrogen. This study had provided a sound nitrogen application strategy for the cultivation of this high-quality cotton line in the field plantation.
[Objective] This study aimed to determine the interactive effects of supple- mental Ca amendment and salinity on germination of sweet sorghum seeds in saline solution culture medium, and investigate the effects of different combinations of Na/Ca ratio in saline soils on the early growth of sweet sorghum plants. [Method] A germi- nation test and a greenhouse pot experiment were conducted to assess the interac- tive effects of calcium addition to culture medium on the germination and seedling growth of sweet sorghum （Sorghum saccharatum Moench） in saline soils with a range of NaYCa ratios. In the germination test, seeds were treated with different combinations of five calcium levels [0, 5, 10, 15, and 20 mmol/L Ca（NO3）2] and five salinity levels （0, 50, 100, 150, and 200 mmol/L NaCI）. In the greenhouse experi- ment, seeds were sown in potting soils containing 3 salinity levels （2.3, 4.7 and 7.0 dS/m） and three Na：Ca ratios （10：0, 10：1, and 5：1）. [Result] In the germination test, Ca addition at 5 mmol/L promoted germination by 5.5%, 9.9%, and 17.0% at the 3.4, 6.7 and 10.1 dS/m salinity levels. The higher Ca level （10 mmol/L） also in- creased germination by 9.1% and 7.8% at the 3.4 and 6.7 dS/m salinity levels. Then even higher Ca addition at 15 and 20 mmol/L appeared to promote germina- tion when culture media had high salinity （10.1 and 13.4 dS/m）. In the greenhouse pot experiment, saline soil amended with supplemental Ca at the 2.3 and 4.7 dS/m salinity levels significantly promoted early seedling growth, with an increase of 6.8% to 28.2% in plant height and 14.3% to 67.9% in whole plant weight. From 28 to 42 d after seeding, the relative growth of seedling was increased by Ca addition, with a reduction of 49.5% to 66.0% in plant height and 4.8% to 61.9% in whole plant weight. From 42 to 56 d after seeding, however, the relative growth of seedling was significantly inhibited by Ca amendment. [Conclusion] Results of this study indicate that appropriate supplemental Ca could impr
为确定盐分对蓖麻的影响,设置0 m M和100 m M 2个盐分浓度Na Cl,研究了4个蓖麻品种种子的吸水和萌发特性。在吸水开始的18 h内,种子吸水快速增加,18 h后增加缓慢,48 h后在0 m M Na Cl水平下种子吸水呈快速增加趋势,而在100 m M Na Cl水平下吸水很少。汾蓖10号和淄蓖7号的吸水量和吸水速率显著高于淄蓖5号和淄蓖8号。与0 m M Na Cl相比,同一品种在100 m M Na Cl下的吸水量和吸水速率明显较低。100m M Na Cl处理对种子萌发具有明显的抑制作用,表现为延迟种子萌发,降低发芽率,抑制芽长和芽粗。综合发芽率、芽长和芽粗相对盐害率,淄蓖5号耐盐能力最强,其次是汾蓖10号,淄蓖7号和淄蓖8号耐盐能力相对较差。本试验通过研究不同蓖麻品种的吸水和萌发特性,为采用外源措施提高种子吸水能力,促进种子萌发和出苗奠定基础。
