This article analyses the effect of the proportion of the different nitrogen forms on key enzyme activity of carbon and nitrogen metabolism under the condition of nutritional water while Tian Yan-7 was used as experim...This article analyses the effect of the proportion of the different nitrogen forms on key enzyme activity of carbon and nitrogen metabolism under the condition of nutritional water while Tian Yan-7 was used as experimental material.The result showed that nitrate reductase(NR) activity in the leaves gradually enhanced with the increase of NO - 3.No matter in root or leaves,glutamina synthetase(GS) activity first enhanced with increasing NH + 4 when NH + 4 was lower than that of NO - 3,and GS activity was the highest when NH + 4and NO - 3 was equal,then GS activity declined with NH + 4 increasing further.In the anaphase of growth,synthetic activity in root of sucrose synthetase(SS) in the mixed NH + 4 and NO - 3 was obviously highr than or NO - 3 alone.Both of the root and sugar yields were the highest when the proportion of NH + 4 and NO - 3 was 1:1.展开更多
Efforts have increased to measure nitrate losses from farmland under different management practices due to environmental and public concerns over levels of nitrate-nitrogen (NO<sub>3</sub>-N) in surface an...Efforts have increased to measure nitrate losses from farmland under different management practices due to environmental and public concerns over levels of nitrate-nitrogen (NO<sub>3</sub>-N) in surface and ground waters. This study evaluated the effect of conventional tillage (CT) and strip tillage (ST) practices and three N application rates on NO3-N concentrations in soil water at a 76 cm depth under irrigated sugarbeet (Beta vulgaris L.) in a clay loam soil. Nitrogen rates were applied as dry urea at 120, 150, 180 kg N ha-1</sup> in 2006;130, 160, 190 kg N ha-1 in 2007;and 110, 140, 170 kg N ha<sup>-1</sup> in 2008. Soil water volumes were measured weekly during each growing season using three ceramic suction cup samplers per plot placed at a 76 cm depth below the soil surface under each tillage. Results indicated that NO<sub>3</sub>-N concentrations at the 76 cm depth in the soil profile were not significantly affected by either tillage practice or by N application rate due to soil variability across the field and due to suction cup samplers’ biased estimate of soil water. The three N rates under CT and ST practices maintained NO<sub>3</sub>-N concentrations below the root zone to levels exceeding the 10 mg L<sup>-1</sup> safe drinking water maximum level in all three years. There were large variations in NO<sub>3</sub>-N concentrations among replicates within each tillage and N rate that were likely caused by variability in soil physical, hydraulic and chemical properties that impacted water movement through the soil profile, N dynamics and leaching below the root zone of sugarbeet. In conclusion, suction cup samplers are point water measurement devices that reveal considerable variability among replicates within each treatment due to the heterogeneity of field soils. Further, these samplers are not recommended in heterogeneous soils with preferential flow characteristics.展开更多
The impact on soil of applying sugarbeet vinasses （V） was analyzed through a field experiment in horticulture greenhouse, arranged in a 23 factorial design. Two levels of three independent variables--application of ...The impact on soil of applying sugarbeet vinasses （V） was analyzed through a field experiment in horticulture greenhouse, arranged in a 23 factorial design. Two levels of three independent variables--application of V, use of polyethylene cover （PC） on the soil. and soil depth （D）---on various dependent variables were studied. Vinasses favoured crop yield and reduced the number of Meloidogyne incognita juveniles in soil. The concentrations ofN. P and K increased with the interaction VxD, with PC also increasing N concentration. The amounts of humic acids and humin decreased with D; fulvic acid concentration increased with V, but decreased with the interaction VxPC. Soil physical factors were improved mainly with D and V. Aromaticity of humic acid-like fractions increased ~＇itb V. In general, V showed significant effects mainly on the topsoil, suggesting low leaching risks. The results indicate that the levels of the independent factors improving a group of variables were not the same that those contributing to another group. Therefore, their best combination should be determined for each scenario to achieve optimum agroecological performance.展开更多
利用常规研究方法,对甜菜单体附加系M 14品系(B eta vu lg aris L.,VV+1C、2n=18+1)的生殖方式进行细胞学与胚胎学研究.结果表明:(1)甜菜单体附加系M 14的4代细胞学检查表明:染色体组分别为VV+1C、2n=18+1;VV+0、2n=18+0;VV+2C、2n=18+2...利用常规研究方法,对甜菜单体附加系M 14品系(B eta vu lg aris L.,VV+1C、2n=18+1)的生殖方式进行细胞学与胚胎学研究.结果表明:(1)甜菜单体附加系M 14的4代细胞学检查表明:染色体组分别为VV+1C、2n=18+1;VV+0、2n=18+0;VV+2C、2n=18+2;VVV+0、2n=27+0;VVV+1C、2n=27+1;VVV+2C、2n=27+2等,其中VV+1C、2n=18+1的植株传递率平均为96.7%,表现为稳定传递,具有二倍体孢子无融合生殖特性;其余各种分离植株的传递率总计为3.25%,有性生殖发生率较低.(2)胚胎学研究表明,二倍体孢子无融合生殖的胚珠中,珠孔处看不到花粉管,胚囊没有发生受精作用.2个助细胞提前退化,半数卵细胞的极性与正常卵细胞相反;卵与次生核不经受精而自发分裂,卵细胞自发分裂产生无性胚,次生核自发分裂产生核型胚乳,而且次生核自发分裂早于卵细胞分裂;有性生殖胚珠中,珠孔处可见多条花粉管,胚囊里见到精卵融合的图像.表明甜菜单体附加系M 14是以二倍体孢子无融合生殖为主要繁殖方式,有性生殖为次要敏殖方式的兼性无融合生殖体.展开更多
文摘This article analyses the effect of the proportion of the different nitrogen forms on key enzyme activity of carbon and nitrogen metabolism under the condition of nutritional water while Tian Yan-7 was used as experimental material.The result showed that nitrate reductase(NR) activity in the leaves gradually enhanced with the increase of NO - 3.No matter in root or leaves,glutamina synthetase(GS) activity first enhanced with increasing NH + 4 when NH + 4 was lower than that of NO - 3,and GS activity was the highest when NH + 4and NO - 3 was equal,then GS activity declined with NH + 4 increasing further.In the anaphase of growth,synthetic activity in root of sucrose synthetase(SS) in the mixed NH + 4 and NO - 3 was obviously highr than or NO - 3 alone.Both of the root and sugar yields were the highest when the proportion of NH + 4 and NO - 3 was 1:1.
文摘Efforts have increased to measure nitrate losses from farmland under different management practices due to environmental and public concerns over levels of nitrate-nitrogen (NO<sub>3</sub>-N) in surface and ground waters. This study evaluated the effect of conventional tillage (CT) and strip tillage (ST) practices and three N application rates on NO3-N concentrations in soil water at a 76 cm depth under irrigated sugarbeet (Beta vulgaris L.) in a clay loam soil. Nitrogen rates were applied as dry urea at 120, 150, 180 kg N ha-1</sup> in 2006;130, 160, 190 kg N ha-1 in 2007;and 110, 140, 170 kg N ha<sup>-1</sup> in 2008. Soil water volumes were measured weekly during each growing season using three ceramic suction cup samplers per plot placed at a 76 cm depth below the soil surface under each tillage. Results indicated that NO<sub>3</sub>-N concentrations at the 76 cm depth in the soil profile were not significantly affected by either tillage practice or by N application rate due to soil variability across the field and due to suction cup samplers’ biased estimate of soil water. The three N rates under CT and ST practices maintained NO<sub>3</sub>-N concentrations below the root zone to levels exceeding the 10 mg L<sup>-1</sup> safe drinking water maximum level in all three years. There were large variations in NO<sub>3</sub>-N concentrations among replicates within each tillage and N rate that were likely caused by variability in soil physical, hydraulic and chemical properties that impacted water movement through the soil profile, N dynamics and leaching below the root zone of sugarbeet. In conclusion, suction cup samplers are point water measurement devices that reveal considerable variability among replicates within each treatment due to the heterogeneity of field soils. Further, these samplers are not recommended in heterogeneous soils with preferential flow characteristics.
文摘The impact on soil of applying sugarbeet vinasses （V） was analyzed through a field experiment in horticulture greenhouse, arranged in a 23 factorial design. Two levels of three independent variables--application of V, use of polyethylene cover （PC） on the soil. and soil depth （D）---on various dependent variables were studied. Vinasses favoured crop yield and reduced the number of Meloidogyne incognita juveniles in soil. The concentrations ofN. P and K increased with the interaction VxD, with PC also increasing N concentration. The amounts of humic acids and humin decreased with D; fulvic acid concentration increased with V, but decreased with the interaction VxPC. Soil physical factors were improved mainly with D and V. Aromaticity of humic acid-like fractions increased ~＇itb V. In general, V showed significant effects mainly on the topsoil, suggesting low leaching risks. The results indicate that the levels of the independent factors improving a group of variables were not the same that those contributing to another group. Therefore, their best combination should be determined for each scenario to achieve optimum agroecological performance.
文摘利用常规研究方法,对甜菜单体附加系M 14品系(B eta vu lg aris L.,VV+1C、2n=18+1)的生殖方式进行细胞学与胚胎学研究.结果表明:(1)甜菜单体附加系M 14的4代细胞学检查表明:染色体组分别为VV+1C、2n=18+1;VV+0、2n=18+0;VV+2C、2n=18+2;VVV+0、2n=27+0;VVV+1C、2n=27+1;VVV+2C、2n=27+2等,其中VV+1C、2n=18+1的植株传递率平均为96.7%,表现为稳定传递,具有二倍体孢子无融合生殖特性;其余各种分离植株的传递率总计为3.25%,有性生殖发生率较低.(2)胚胎学研究表明,二倍体孢子无融合生殖的胚珠中,珠孔处看不到花粉管,胚囊没有发生受精作用.2个助细胞提前退化,半数卵细胞的极性与正常卵细胞相反;卵与次生核不经受精而自发分裂,卵细胞自发分裂产生无性胚,次生核自发分裂产生核型胚乳,而且次生核自发分裂早于卵细胞分裂;有性生殖胚珠中,珠孔处可见多条花粉管,胚囊里见到精卵融合的图像.表明甜菜单体附加系M 14是以二倍体孢子无融合生殖为主要繁殖方式,有性生殖为次要敏殖方式的兼性无融合生殖体.
