氮沉降改变森林生态系统养分平衡,影响土壤中营养元素循环和微生物养分代谢过程。五大连池火山熔岩台地由于自身养分匮乏,植被恢复受到养分条件的制约,但土壤微生物与植物养分限制的协同响应机制仍缺乏深入研究。本研究以香杨(Populus k...氮沉降改变森林生态系统养分平衡,影响土壤中营养元素循环和微生物养分代谢过程。五大连池火山熔岩台地由于自身养分匮乏,植被恢复受到养分条件的制约,但土壤微生物与植物养分限制的协同响应机制仍缺乏深入研究。本研究以香杨(Populus koreana)矮曲林为研究对象,模拟5个氮添加梯度,分别为CK(0 g N m^(-2)a^(-1))、N1(2 g N m^(-2)a^(-1))、N_(2)(4 g N m^(-2)a^(-1))、N_(3)(8 g N m^(-2)a^(-1))和N4(16 g N m^(-2)a^(-1)),施肥两年后测定土壤养分和微生物C、N、P含量及胞外酶活性,采用生态酶化学计量学方法,揭示微生物代谢对碳、氮、磷的限制模式,旨在探究外源氮添加对土壤微生物代谢限制产生的影响。结果表明,(1)添加氮后土壤中C-获取酶,N-获取酶和P-获取酶的活性均显著升高,随着氮添加量的递增,三种酶的活性变化趋势表现为呈先上升后下降,N_(3)处理C-获取酶和P-获取酶活性最高,而N_(2)处理N-获取酶活性最高;(2)土壤胞外酶的EEA_(C∶P)和EEA_(N∶P)呈先升高后降低的趋势,N_(2)处理达到最高,而EEA_(C∶N)呈先降低后增加再降低的趋势,N_(3)处理最高;(3)矢量模型分析发现所有氮处理土壤矢量角度均大于45°,随着氮添加量的增多呈先减少后增加的趋势;(4)冗余分析发现土壤养分是影响胞外酶活性和胞外酶化学计量比的关键因子,TP与矢量长度和矢量角度均呈显著正相关关系(P<0.05)。结果表明,氮沉降可以提高土壤胞外酶活性,影响土壤微生物的养分限制,促进土壤生物化学循环,研究结果为气候变化下森林生态系统的适应性管理提供重要科学依据。展开更多
Rice is a poor source of folate,an essential micronutrient for the body.Biofortification offers an effective way to enhance the folate content of rice and alleviate folate deficiencies in humans.In this study,we confi...Rice is a poor source of folate,an essential micronutrient for the body.Biofortification offers an effective way to enhance the folate content of rice and alleviate folate deficiencies in humans.In this study,we confirmed that OsADCS and OsGTPCHI,encoding the initial enzymes necessary for folate synthesis,positively regulate folate accumulation in knockout mutants of both japonica and indica rice backgrounds.The folate content in the low-folate japonica variety was slightly increased by the expression of the indica alleles driven by the endosperm-specific promoter.We further obtained co-expression lines by stacking OsADCS and OsGTPCHI genes;the folate accumulation in brown rice and polished rice reached 5.65μg/g and 2.95μg/g,respectively,representing 37.9-fold and 26.5-fold increases compared with the wild type.Transcriptomic analysis of rice grains from six transgenic lines showed that folate changes affected biological pathways involved in the synthesis and metabolism of rice seed storage substances,while the expression of other folate synthesis genes was weakly regulated.In addition,we identified Aus rice as a high-folate germplasm carrying superior haplotypes of OsADCS and OsGTPCHI through natural variation.This study provides an alternative and effective complementary strategy for rice biofortification,promoting the rational combination of metabolic engineering and conventional breeding to breed high-folate varieties.展开更多
文摘氮沉降改变森林生态系统养分平衡,影响土壤中营养元素循环和微生物养分代谢过程。五大连池火山熔岩台地由于自身养分匮乏,植被恢复受到养分条件的制约,但土壤微生物与植物养分限制的协同响应机制仍缺乏深入研究。本研究以香杨(Populus koreana)矮曲林为研究对象,模拟5个氮添加梯度,分别为CK(0 g N m^(-2)a^(-1))、N1(2 g N m^(-2)a^(-1))、N_(2)(4 g N m^(-2)a^(-1))、N_(3)(8 g N m^(-2)a^(-1))和N4(16 g N m^(-2)a^(-1)),施肥两年后测定土壤养分和微生物C、N、P含量及胞外酶活性,采用生态酶化学计量学方法,揭示微生物代谢对碳、氮、磷的限制模式,旨在探究外源氮添加对土壤微生物代谢限制产生的影响。结果表明,(1)添加氮后土壤中C-获取酶,N-获取酶和P-获取酶的活性均显著升高,随着氮添加量的递增,三种酶的活性变化趋势表现为呈先上升后下降,N_(3)处理C-获取酶和P-获取酶活性最高,而N_(2)处理N-获取酶活性最高;(2)土壤胞外酶的EEA_(C∶P)和EEA_(N∶P)呈先升高后降低的趋势,N_(2)处理达到最高,而EEA_(C∶N)呈先降低后增加再降低的趋势,N_(3)处理最高;(3)矢量模型分析发现所有氮处理土壤矢量角度均大于45°,随着氮添加量的增多呈先减少后增加的趋势;(4)冗余分析发现土壤养分是影响胞外酶活性和胞外酶化学计量比的关键因子,TP与矢量长度和矢量角度均呈显著正相关关系(P<0.05)。结果表明,氮沉降可以提高土壤胞外酶活性,影响土壤微生物的养分限制,促进土壤生物化学循环,研究结果为气候变化下森林生态系统的适应性管理提供重要科学依据。
基金supported by the Central Public-Interest Scientific Institution Basal Research Fund,China(Grant No.CPSIBRF-CNRRI-202403)。
文摘Rice is a poor source of folate,an essential micronutrient for the body.Biofortification offers an effective way to enhance the folate content of rice and alleviate folate deficiencies in humans.In this study,we confirmed that OsADCS and OsGTPCHI,encoding the initial enzymes necessary for folate synthesis,positively regulate folate accumulation in knockout mutants of both japonica and indica rice backgrounds.The folate content in the low-folate japonica variety was slightly increased by the expression of the indica alleles driven by the endosperm-specific promoter.We further obtained co-expression lines by stacking OsADCS and OsGTPCHI genes;the folate accumulation in brown rice and polished rice reached 5.65μg/g and 2.95μg/g,respectively,representing 37.9-fold and 26.5-fold increases compared with the wild type.Transcriptomic analysis of rice grains from six transgenic lines showed that folate changes affected biological pathways involved in the synthesis and metabolism of rice seed storage substances,while the expression of other folate synthesis genes was weakly regulated.In addition,we identified Aus rice as a high-folate germplasm carrying superior haplotypes of OsADCS and OsGTPCHI through natural variation.This study provides an alternative and effective complementary strategy for rice biofortification,promoting the rational combination of metabolic engineering and conventional breeding to breed high-folate varieties.
