以7年生烟富3/M26/平邑甜茶为试材,采用^(15)N同位素示踪技术,研究不同供氮水平[低氮(100 kg N·hm^(-2),N_(100))、中氮(200 kg N·hm^(-2),N_(200))和高氮(300 kg N·hm^(-2),N_(300))]对烟富3/M26/平邑甜茶^(15)N-尿素...以7年生烟富3/M26/平邑甜茶为试材,采用^(15)N同位素示踪技术,研究不同供氮水平[低氮(100 kg N·hm^(-2),N_(100))、中氮(200 kg N·hm^(-2),N_(200))和高氮(300 kg N·hm^(-2),N_(300))]对烟富3/M26/平邑甜茶^(15)N-尿素吸收、利用、损失及产量和品质的影响.结果表明:不同供氮水平植株的生长状况及氮素吸收、利用和损失特性差异显著.N_(200)处理植株叶绿素含量(SPAD)、光合速率(Pn)、叶片全氮含量和生物量显著高于N_(100)和N_(300)处理,植株根冠比也显著增加.不同供氮水平下植株各器官对氮的吸收能力(Ndff值)存在显著差异,各测定时期果实(花)、叶片、一年生枝、多年生枝和中心干的Ndff值均为N_(100)>N_(200)>N_(300);而根的Ndff值在盛花期和春梢缓长期为N_(100)>N_(200)>N_(300),在秋梢生长期、果实膨大期和果实成熟期为N_(200)>N_(100)>N_(300).在果实成熟期,N_(200)处理^(15)N肥料利用率为23.6%,显著高于N_(100)(16.3%)和N_(300)处理(14.4%),而^(15)N损失率为56.4%,显著低于N_(100)(60.6%)和N_(300)处理(66.1%).不同供氮水平植株的平均单果质量、单株产量、可溶性固形物、硬度、可溶性糖、可滴定酸、糖酸比均存在显著差异,且均以N_(200)处理最高,其次是N_(300)处理,N_(100)处理最低.展开更多
Bi-directional translocation and degradation of Arginine (Arg) along the arbuscular mycorrhizal (AM) fungal mycelium were testified through 15N and/or 13C isotopic labeling. In vitro mycorrhizas of Glomus intraradices...Bi-directional translocation and degradation of Arginine (Arg) along the arbuscular mycorrhizal (AM) fungal mycelium were testified through 15N and/or 13C isotopic labeling. In vitro mycorrhizas of Glomus intraradices and Ri T-DNA-transformed carrot roots were grown in dual compartment Petri dishes. [15N- and/or13C]Arg was supplied to either the fungal compartment or the mycorrhizal compartment or separate dishes containing the uncolonized roots. The levels and labeling of free amino acids (AAs) in the mycorrhizal roots and in the extraradical mycelia(ERM) were measured by gas chromatogra- phy/mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). The ERM of AM fungi exposed in either NH4+ or urea as sole external nitrogen source had much higher 15N enrichment of Arg, compared with those in nitrate or exogenous Arg; however, glycerol supplied as an external car- bon source to the ERM had no significant effect on the level of Arg in the ERM. Meanwhile, Arg bio- synthesized in the ERM could be translocated intact to the mycorrhizal roots and thereby the level of Arg in the mycorrhizal roots increased to about 20% after culture of ERM in 4 mmol/L NH4+ for 6 weeks. Also Arg was found to be bi-directionally transported along the AM fungal mycelium through [U-13C]Arg labeling either in the mycorrhizal compartment or in the fungal compartment. Once Arg was translo- cated to the potential N-limited sites, it would be further degraded into ornithine (Orn) and urea since either [U-13C] or [U-15N/U-13C]Orn was apparently shown up in the mycorrhizal root tissues when [U-13C] or [U-15N/U-13C]Arg was labeled in the fungal compartment, respectively. Evidently Orn formation indi- cated the ongoing activities of Arg translocation and degradation through the urea cycle in AM fungal mycelium.展开更多
以施氮量调控氮代谢,提高氮肥利用率为目标,利用15 N研究了包膜尿素(CU100、150和225kg/hm2)和普通尿素(150和225kg/hm2)对夏玉米产量、生物量、氮肥利用率以及各器官氮分配的影响。结果表明:包膜尿素比普通尿素显著增加玉米从肥料中的...以施氮量调控氮代谢,提高氮肥利用率为目标,利用15 N研究了包膜尿素(CU100、150和225kg/hm2)和普通尿素(150和225kg/hm2)对夏玉米产量、生物量、氮肥利用率以及各器官氮分配的影响。结果表明:包膜尿素比普通尿素显著增加玉米从肥料中的吸氮量,显著增加地上部生物量;15N包膜尿素肥料利用率(15NUE,nitrogen use efficiency)显著高于普通尿素;15N包膜尿素在玉米器官的分配与普通尿素有差异,前者从肥料中吸氮量为籽粒>叶片>秸秆>玉米芯>苞叶,而后者为籽粒>秸秆>叶片>玉米芯>苞叶;非标记时,2种肥料在玉米器官的分配顺序相同,都为籽粒>叶片>秸秆>玉米芯>苞叶。玉米地上部吸氮量、籽粒氮收获指数和籽粒产量没有因不同氮肥形态和施氮量而产生显著变化,这可能是前茬冬小麦季节温度低,冬小麦吸氮少,收获后残留土壤的NO3-N含量高,所以夏玉米吸氮量主要受自身生长势或生长速率控制,受肥料种类和施氮量的影响较小。展开更多
Ammonia volatilization loss and ^15N balance were studied in a rice field at three different stages after urea application in Taihu Lake area with a micrometeorological technique. Factors such as climate and the NH4^...Ammonia volatilization loss and ^15N balance were studied in a rice field at three different stages after urea application in Taihu Lake area with a micrometeorological technique. Factors such as climate and the NH4^＋-N concentration in the field floodwater affecting ammonia loss were also investigated. Results show that the ammonia loss by volatilization accounted for 18.6%-38.7% of urea applied at different stages, the greatest loss took place when urea was applied at the tillering stage, the smallest at the ear bearing stage, and the intermediate loss at the basal stage. The greatest loss took place within 7 d following the fertilizer application. Ammonia volatilization losses at three fertilization stages were significantly correlated with the ammonium concentration in the field floodwater after the fertilizer was applied. ^15N balance experiment indicated that the use efficiency of urea by rice plants ranged between 24.4% and 28.1%. At the early stage of rice growth, the fertilizer nitrogen use efficiency was rather low, only about 12%. The total amount of nitrogen lost from different fertilization stages in the rice field was 44.1%-54.4%, and the ammonia volatilization loss was 25.4%-33.3%. Reducing ammonia loss is an important treatment for improving N use efficiency.展开更多
文摘以7年生烟富3/M26/平邑甜茶为试材,采用^(15)N同位素示踪技术,研究不同供氮水平[低氮(100 kg N·hm^(-2),N_(100))、中氮(200 kg N·hm^(-2),N_(200))和高氮(300 kg N·hm^(-2),N_(300))]对烟富3/M26/平邑甜茶^(15)N-尿素吸收、利用、损失及产量和品质的影响.结果表明:不同供氮水平植株的生长状况及氮素吸收、利用和损失特性差异显著.N_(200)处理植株叶绿素含量(SPAD)、光合速率(Pn)、叶片全氮含量和生物量显著高于N_(100)和N_(300)处理,植株根冠比也显著增加.不同供氮水平下植株各器官对氮的吸收能力(Ndff值)存在显著差异,各测定时期果实(花)、叶片、一年生枝、多年生枝和中心干的Ndff值均为N_(100)>N_(200)>N_(300);而根的Ndff值在盛花期和春梢缓长期为N_(100)>N_(200)>N_(300),在秋梢生长期、果实膨大期和果实成熟期为N_(200)>N_(100)>N_(300).在果实成熟期,N_(200)处理^(15)N肥料利用率为23.6%,显著高于N_(100)(16.3%)和N_(300)处理(14.4%),而^(15)N损失率为56.4%,显著低于N_(100)(60.6%)和N_(300)处理(66.1%).不同供氮水平植株的平均单果质量、单株产量、可溶性固形物、硬度、可溶性糖、可滴定酸、糖酸比均存在显著差异,且均以N_(200)处理最高,其次是N_(300)处理,N_(100)处理最低.
基金Supported by Science and Technology Department of Zhejiang Province (Grant No. 2006C22009).
文摘Bi-directional translocation and degradation of Arginine (Arg) along the arbuscular mycorrhizal (AM) fungal mycelium were testified through 15N and/or 13C isotopic labeling. In vitro mycorrhizas of Glomus intraradices and Ri T-DNA-transformed carrot roots were grown in dual compartment Petri dishes. [15N- and/or13C]Arg was supplied to either the fungal compartment or the mycorrhizal compartment or separate dishes containing the uncolonized roots. The levels and labeling of free amino acids (AAs) in the mycorrhizal roots and in the extraradical mycelia(ERM) were measured by gas chromatogra- phy/mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). The ERM of AM fungi exposed in either NH4+ or urea as sole external nitrogen source had much higher 15N enrichment of Arg, compared with those in nitrate or exogenous Arg; however, glycerol supplied as an external car- bon source to the ERM had no significant effect on the level of Arg in the ERM. Meanwhile, Arg bio- synthesized in the ERM could be translocated intact to the mycorrhizal roots and thereby the level of Arg in the mycorrhizal roots increased to about 20% after culture of ERM in 4 mmol/L NH4+ for 6 weeks. Also Arg was found to be bi-directionally transported along the AM fungal mycelium through [U-13C]Arg labeling either in the mycorrhizal compartment or in the fungal compartment. Once Arg was translo- cated to the potential N-limited sites, it would be further degraded into ornithine (Orn) and urea since either [U-13C] or [U-15N/U-13C]Orn was apparently shown up in the mycorrhizal root tissues when [U-13C] or [U-15N/U-13C]Arg was labeled in the fungal compartment, respectively. Evidently Orn formation indi- cated the ongoing activities of Arg translocation and degradation through the urea cycle in AM fungal mycelium.
文摘以施氮量调控氮代谢,提高氮肥利用率为目标,利用15 N研究了包膜尿素(CU100、150和225kg/hm2)和普通尿素(150和225kg/hm2)对夏玉米产量、生物量、氮肥利用率以及各器官氮分配的影响。结果表明:包膜尿素比普通尿素显著增加玉米从肥料中的吸氮量,显著增加地上部生物量;15N包膜尿素肥料利用率(15NUE,nitrogen use efficiency)显著高于普通尿素;15N包膜尿素在玉米器官的分配与普通尿素有差异,前者从肥料中吸氮量为籽粒>叶片>秸秆>玉米芯>苞叶,而后者为籽粒>秸秆>叶片>玉米芯>苞叶;非标记时,2种肥料在玉米器官的分配顺序相同,都为籽粒>叶片>秸秆>玉米芯>苞叶。玉米地上部吸氮量、籽粒氮收获指数和籽粒产量没有因不同氮肥形态和施氮量而产生显著变化,这可能是前茬冬小麦季节温度低,冬小麦吸氮少,收获后残留土壤的NO3-N含量高,所以夏玉米吸氮量主要受自身生长势或生长速率控制,受肥料种类和施氮量的影响较小。
文摘Ammonia volatilization loss and ^15N balance were studied in a rice field at three different stages after urea application in Taihu Lake area with a micrometeorological technique. Factors such as climate and the NH4^＋-N concentration in the field floodwater affecting ammonia loss were also investigated. Results show that the ammonia loss by volatilization accounted for 18.6%-38.7% of urea applied at different stages, the greatest loss took place when urea was applied at the tillering stage, the smallest at the ear bearing stage, and the intermediate loss at the basal stage. The greatest loss took place within 7 d following the fertilizer application. Ammonia volatilization losses at three fertilization stages were significantly correlated with the ammonium concentration in the field floodwater after the fertilizer was applied. ^15N balance experiment indicated that the use efficiency of urea by rice plants ranged between 24.4% and 28.1%. At the early stage of rice growth, the fertilizer nitrogen use efficiency was rather low, only about 12%. The total amount of nitrogen lost from different fertilization stages in the rice field was 44.1%-54.4%, and the ammonia volatilization loss was 25.4%-33.3%. Reducing ammonia loss is an important treatment for improving N use efficiency.
