对水分胁迫下不同根系大小的春小麦籽粒产量与水分利用效率、相对生长速度和根系功能效率之间的关系进行了研究.实验分为3个水分处理和3个根系大小处理,3个水分处理分别是土壤含水量保持在田间持水量的80%～90% H ,50%～60% M 和30%～40...对水分胁迫下不同根系大小的春小麦籽粒产量与水分利用效率、相对生长速度和根系功能效率之间的关系进行了研究.实验分为3个水分处理和3个根系大小处理,3个水分处理分别是土壤含水量保持在田间持水量的80%～90% H ,50%～60% M 和30%～40% L .根系大小的处理是 1 大根系处理 B , 2 中根系处理 M 和 3 小根系处理 S .实验结果表明,在中度和重度干旱条件下小根系处理 MS和LS 的作物具有较高的WEUg、WUEdm、相对生长速度、根系功能效率和籽粒产量;在高水分处理中,上述参数的数值在大根系处理中相对较高.根呼吸耗C量在作物的整个生育期中都占有十分重要的地位,尽管根呼吸耗C比例随作物的生长而呈同步增加的趋势,但实际耗C量却呈逐步下降的趋势,同一时期作物的根呼吸速率与土壤含水量之间存在正相关关系,说明适当降低土壤含水量可以有效地减少根呼吸耗C量,有利于提高作物的存活率.在干旱半干旱地区,春小麦的根功能效率尚未达到最高值,作物产量仍有潜力可挖,通过适时补灌和减少同化物向根系分配的比例和根系对同化产物的消耗量来达到提高春小麦籽粒产量的方法是可行的,但不是长久之计.展开更多
This paper reports the cloning and expression analysis of a high-affinity nitrate transporter inwheat ( Triticurn aestivurn L.). A full-length cDNA, TaNRT2.3(accession number AY053452), was isolatedfrom NO3--induced r...This paper reports the cloning and expression analysis of a high-affinity nitrate transporter inwheat ( Triticurn aestivurn L.). A full-length cDNA, TaNRT2.3(accession number AY053452), was isolatedfrom NO3--induced roots of wheat. The cDNA encodes a polypeptide with 507 amino acids and 12transmembrane domains, belongs to nitrate/nitrite porter (NNP) family within the major facilitator superfamily(MFS), and is closely related to other NRT2 proteins from plants. The expressions of TaNtTT2 genes inwheat tissues were analyzed using Northern blot, results indicated that TaNRT2 were induced specificallyin roots but not in shoots in response to both low (5-200 μmol/L) and high (2.0 retool/L) concentrationsof NO^-. TaNRT2transcripts were undetectable in N-deprived or NH4^+grown plant roots. The significantcorrelation between the time course of TaNtTT2transcription accumulation in the roots of wheat plantsgrown in 0.2 mmol/L NO3- and the time course of the nitrate uptake rates by wheat plants grown under thesame conditions suggested that TaNtTT2 played an important role in high-affinity NO3-uptake. Using thesplit root system, we found that supplying NO3- to one part of the roots induced the expression of TaNtTT2in the other part not supplied with NO3- or supplied with NH4^+, which implied that N cycling within plantsacted as a regulatory signal for N uptake.展开更多
文摘对水分胁迫下不同根系大小的春小麦籽粒产量与水分利用效率、相对生长速度和根系功能效率之间的关系进行了研究.实验分为3个水分处理和3个根系大小处理,3个水分处理分别是土壤含水量保持在田间持水量的80%～90% H ,50%～60% M 和30%～40% L .根系大小的处理是 1 大根系处理 B , 2 中根系处理 M 和 3 小根系处理 S .实验结果表明,在中度和重度干旱条件下小根系处理 MS和LS 的作物具有较高的WEUg、WUEdm、相对生长速度、根系功能效率和籽粒产量;在高水分处理中,上述参数的数值在大根系处理中相对较高.根呼吸耗C量在作物的整个生育期中都占有十分重要的地位,尽管根呼吸耗C比例随作物的生长而呈同步增加的趋势,但实际耗C量却呈逐步下降的趋势,同一时期作物的根呼吸速率与土壤含水量之间存在正相关关系,说明适当降低土壤含水量可以有效地减少根呼吸耗C量,有利于提高作物的存活率.在干旱半干旱地区,春小麦的根功能效率尚未达到最高值,作物产量仍有潜力可挖,通过适时补灌和减少同化物向根系分配的比例和根系对同化产物的消耗量来达到提高春小麦籽粒产量的方法是可行的,但不是长久之计.
文摘This paper reports the cloning and expression analysis of a high-affinity nitrate transporter inwheat ( Triticurn aestivurn L.). A full-length cDNA, TaNRT2.3(accession number AY053452), was isolatedfrom NO3--induced roots of wheat. The cDNA encodes a polypeptide with 507 amino acids and 12transmembrane domains, belongs to nitrate/nitrite porter (NNP) family within the major facilitator superfamily(MFS), and is closely related to other NRT2 proteins from plants. The expressions of TaNtTT2 genes inwheat tissues were analyzed using Northern blot, results indicated that TaNRT2 were induced specificallyin roots but not in shoots in response to both low (5-200 μmol/L) and high (2.0 retool/L) concentrationsof NO^-. TaNRT2transcripts were undetectable in N-deprived or NH4^+grown plant roots. The significantcorrelation between the time course of TaNtTT2transcription accumulation in the roots of wheat plantsgrown in 0.2 mmol/L NO3- and the time course of the nitrate uptake rates by wheat plants grown under thesame conditions suggested that TaNtTT2 played an important role in high-affinity NO3-uptake. Using thesplit root system, we found that supplying NO3- to one part of the roots induced the expression of TaNtTT2in the other part not supplied with NO3- or supplied with NH4^+, which implied that N cycling within plantsacted as a regulatory signal for N uptake.
