C_4作物FACE(free-air CO_2 enrichment)研究进展

持续迅速上升的大气二氧化碳浓度([CO2])是全球变暖最大的驱动因子,但其作为光合作用底物直接增加了作物的生产力。相比C3作物,人们对未来高浓度CO2情形下C4作物的响应规律认识较少。与封闭或半封闭气室研究相比,FACE(free-airCO2 enrichment)试验在空气自由流动的大田条件下对作物表现进行研究,它提供了对未来作物生长环境的真实模拟,因此提供了评估CO2肥料效应以及揭示植物响应机制的最好机会。作为人类重要的粮食和饲料来源,高粱和玉米是最重要的C4作物。在简介美国玉米和高粱FACE系统的基础上,综述了FACE情形下高浓度CO2(模拟本世纪中叶大气CO2浓度,即550μmol/mol)对两大作物生理、生长和产量以及土壤特性等方面的影响,同时比较了与气室研究结果的异同点。(1)FACE使干旱条件下两作物光合作用显著增强,但湿润条件下没有影响;FACE条件下高粱出现光合适应现象,而玉米没有;(2)FACE使两作物气孔导度大幅下降,导致叶温升高、蒸腾速率下降、蒸发蒸腾总量减少或没有变化、叶片总水势和水分利用效率增加或没有变化;(3)FACE对两作物物候期和化学组分影响很少;(4)FACE使干旱条件下两作物生长和产量略有增加,但湿润条件下没有影响;(5)FACE使高粱田土壤丛枝状菌根真菌的长度和易提取胶状物质浓度显著增加,导致水稳性土壤团聚体增加;FACE对高粱田N2O或含氮气体(N2O+N2)的排放没有影响;(6)高浓度CO2对两作物气孔导度的影响FACE试验明显大于气室试验,而对生长和产量的影响呈相反趋势。阐明CO2与基因型、土壤湿度和大气温度间的互作效应及其机制是下一轮C4作物FACE研究优先考虑的方向,技术的不断进步已为利用大型FACE系统来研究这些互作效应提供了可能。

Elevated CO2 Effects on Lichen Frequencies and Diversity Distributions in Free-Air CO2 Enrichment (FACE) Station

Carbon dioxides (CO2) concentration has become much higher every year and this has already become the global issue. Lichen is a symbiotic organism that is best known as the air pollution indicator. Based on its frequency and diversity distribution, the level of pollution that has been made can be determined. This re-search was conducted in UKM Fernarium Free Air Carbon Dioxides Enrichment Station (FACE Station) with lichen frequencies and diversities observed and analyzed statistically and graphically. Seven species of li-chens were found at the sampling locations. Findings showed that there was significant relationship in lichen frequency and diversity distribution under elevated CO2 inside FACE Station with its surrounding.

Effects of free-air CO_2 enrichment on adventitious root development of rice under low and normal soil nitrogen levels

Free air CO2 enrichment(FACE) and nitrogen(N) have marked effects on rice root growth,and numerical simulation can explain these effects. To further define the effects of FACE on root growth of rice, an experiment was performed, using the hybrid indica cultivar Xianyou63. The effects of increasing atmospheric CO2 concentration [CO2], 200 μmol mol-1higher than ambient, on the growth of rice adventitious roots were evaluated, with two levels of N: low(LN, 125 kg ha-1) and normal(NN, 250 kg ha-1). The results showed a significant increase in both adventitious root number(ARN) and adventitious root length(ARL) under FACE treatment. The application of nitrogen also increased ARN and ARL, but these increases were smaller than that under FACE treatment. On the basis of the FACE experiment, numerical models for rice adventitious root number and length were constructed with time as the driving factor. The models illustrated the dynamic development of rice adventitious root number and length after transplanting, regulated either by atmospheric [CO2] or by N application.The simulation result was supported by statistical tests comparing experimental data from different years, and the model yields realistic predictions of root growth. These results suggest that the models have strong predictive potential under conditions of atmospheric [CO2] rises in the future.

Effect of free-air CO_2 enrichment on nematode communities in a Chinese farmland ecosystem

At a rice wheat rotational free air CO 2 enrichment(FACE) platform, the effect of elevated atmospheric CO 2 on soil nematode communities in a farmland ecosystem was studied. Wheat plots were exposed to elevated atmospheric CO 2(ambient 370 μl/L + 200 μl/L). 32 families and 40 genera of nematode were observed in soil suspensions during the study period. Under FACE treatment, the numbers of total nematodes, bacterivores and fungivores exhibited an increasing trend. Because of the seasonal variation of soil temperature and moisture, the effect of elevated atmospheric CO 2 on soil nematodes was only observed under favorable conditions. The response of nematode communities to elevated atmospheric CO 2 may indicate the change of soil food web.

Effects of Free-air CO2 Enrichment on Root Characteristics and C:N Ratio of Rice at the Heading Stage

A hydroponics experiment was conducted to investigate the rice root growth in FACE （free-air carbon dioxide enrichment）. The root biomass, root volume, ratio of root/shoot, number of adventitious roots and root diameter significantly increased under FACE conditions, while the CO2 enrichment decreased the N concentration in rice roots without any change in the C content, leading to an increase in root C：N ratio. Moreover, the elevated CO2 resulted in a remarkable decrease of root activity, expressed as per unit root dry weight, which might be responsible for decreased N concentration in roots.

Modeling Methane Emissions from Paddy Rice Fields under Elevated Atmospheric Carbon Dioxide Conditions

Abstract Methane （CH4） emissions from paddy rice fields substantially contribute to the dramatic increase of this greenhouse gas in the atmosphere. Due to great concern about climate change, it is necessary to predict the effects of the dramatic increase in atmospheric carbon dioxide （CO2） on CH4 emissions from paddy rice fields. CH4MOD 1.0 is the most widely validated model for simulating CH4 emissions from paddy rice fields exposed to ambient CO2 （hereinafter referred to as aCO2）. We upgraded the model to CH4MOD 2.0 by： （a） modifying the description of the influences of soil Eh and the water regime on CH4 production; （b） adding new features to reflect the regulatory effects of atmospheric CO2 upon methanogenic substrates, soil Eh during drainages, and vascular CH4 transport; and （c） adding a new feature to simulate the influences of nitrogen （N） addition rates on methanogenic substrates under elevated CO2 （hereinafter referred to as eCO2） condition. Validation with 109 observation cases under aC02 condition showed that CHaMOD 2.0 possessed a minor systematic bias in the prediction of seasonally accumulated methane emissions （SAM）. Validation with observations in free-air CO2 enrichment （FACE） experiments in temperate and subtropical climates showed that CH4MOD 2.0 successfully simulated the effects of eCO2 upon SAM from paddy rice fields incorporated with various levels of previous crop residues and/or N fertilizer. Our results imply that CH4MOD 2.0 provides a potential approach for estimating of the effects of elevated atmospheric CO2 upon CHa emissions from regional or global paddy rice fields with various management practices in a changing climate.

Numerical Simulation of Root Growth Dynamics of CO_2-Enriched Hybrid Rice Cultivar Shanyou 63 Under Fully Open-Air Field Conditions

Hybrid indica rice （Oryza sativa L.） cultivars play an important role in rice production system due to its heterosis, resistance to environmental stress, large panicle, and high yield potential. However, no attention has been given to its root growth dynamic responses to rising atmospheric CO2 concentration （[CO2]） in conjunction with nitrogen （N） availability. Free air COz enrichment （FACE） and N have significant effects on rice root growth. In this experiment, a hybrid cultivar Shanyou 63 （Oryza sativa L.） was used to study the effects of FACE and N levels on roots growth of rice. The results showed a significant increase in both adventitious root volume （ARV） and adventitious root dry weight （ARD） under the FACE treatment. The application of nitrogen also increased ARV and ARD, but the increase was smaller than that under FACE treatment. On the basis of the FACE experiment, numerical models for rice adventitious root volume and dry weight were built with the time as the driving factor. The models illustrated the dynamic development of rice adventitious root volume and dry weight after transplanting, regulated either by the influence factor of atmospheric [CO2] or by N application. The models were successfully used to predict ARV and ARD under FACE treatment in a different year with the predicted data being closely related to the actual experimental data. The model had guiding significance to growth regulation of rice root under the condition of atmospheric [CO2] rising in the future.

Responses of rice growth to copper stress under free-air CO_2 enrichment (FACE)

The responses of rice to the second degree contamination of copper were studied by pot experiments under free-air CO2 enrichment (FACE) with 570 μmol·mol-1 of CO2. The results showed that the content of copper in rice leaves was reduced with the CO2 concentration reaching 570 μmol·mol-1 and this happened more significantly under the second degree contamination of copper. Under FACE, activities of superoxide dismutase (SOD) enzyme in rice leaves treated by copper contamination were induced, whereas the contents of glutathione (GSH) and glutathione disulfide (GSSG) had no significant difference from the control. In the presence of ambient CO2, activities of SOD enzyme treated by copper pollution were suppressed during the whole rice growth, however, the contents of GSH and GSSG were induced at tillering and jointing stages, and then restored to the control levels in later growth under the second degree contamination of copper. With the rice growing, the content of malondialdehyde (MDA) rises continuously, but there had been no significant difference between the treatments at the same growth stage. Further studies are needed on the response mechanism of rice to Cu stress under elevated CO2.

开放式空气中CO_2浓度增高(FACE)对常规粳稻蛋白质和氨基酸含量的影响

为了明确未来大气CO2浓度升高对水稻蛋白质营养品质的影响,2009年利用稻田开放式空气CO2浓度增高(FACE,FreeAirCO2 Enrichment)系统,以武运粳21、扬辐粳8号和武粳15为供试品种,研究大田生长期CO2浓度升高200μmol.mol-1对常规粳稻蛋白质营养品质的影响。结果表明:大气CO2浓度增加使所有供试品种精米蛋白质含量平均下降5.6%,使氨基酸、必需和非必需氨基酸总量平均分别下降7.6%、6.7%和7.9%,均达极显著水平。大气CO2浓度增加使供试品种精米必需氨基酸占氨基酸总量百分比显著增加,使非必需氨基酸占氨基酸总量百分比显著下降,但对精米中必需和非必需氨基酸的相对含量无显著影响。从氨基酸组分看,大气CO2浓度增加使供试品种精米中7种必需氨基酸和8种非必需氨基酸的含量均显著或极显著下降。CO2处理与品种对精米蛋白质含量、氨基酸总量、必需和非必需氨基酸总量以及部分氨基酸组分有一定的互作效应,武运粳21上述参数对高浓度CO2的响应大于扬辐粳8号或武粳15对应参数的响应。以上结果说明本世纪中叶大气中的CO2浓度将使粳稻蛋白质营养品质下降,不同品种下降幅度存在一定差异。

臭氧胁迫使两优培九倒伏风险增加——FACE研究

近地层臭氧(O3)浓度升高使作物生长发育受到抑制进而使产量下降,但O3胁迫条件下作物抗倒性状的变化及其可能原因均不清楚。FACE(Free Air gas Concentration Enrichment)试验在很少扰动的自然农田实施,其特有的空间优势为研究这一问题提供了最好的机会。依托全球唯一的稻田臭氧FACE技术平台,以杂交稻两优培九为供试材料,设置大气背景O3浓度和高O3浓度两个水平首次对这一问题进行了实验研究。结果表明:高O3浓度使水稻抽穗期单茎(去除叶鞘)倒5、倒4和倒3节间的平均倒伏指数分别增加25%、16%和14%,使抽穗后35 d对应节间倒伏指数分别增加13%、12%和2%,除抽穗后35 d倒3节间外均达显著或极显著水平;高浓度O3使水稻抽穗期和抽穗后35 d植株倒5、倒4和倒3节间的抗折力和弯曲力矩均下降,前者降幅明显大于后者;高O3浓度对抽穗期和抽穗后35 d倒5、倒4、倒3和倒2和倒1节间的长度和粗度影响较小,但使各节间单位长度鲜重和干重一致下降,以单位长度干重降幅更大;高O3浓度使结实期倒5、倒4、倒3、倒2和倒1节间可溶性糖和淀粉含有率均下降,抽穗后35 d降幅大于抽穗期。以上数据表明,未来高浓度臭氧环境条件下两优培九结实期的倒伏风险明显增加,这主要与基部节间抗折能力明显削弱有关,而后者可能又与节间充实程度下降有关。

二氧化碳、施氮量和移栽密度对汕优63产量形成的影响--FACE研究

大气二氧化碳(CO2)浓度升高使水稻产量增加,但这种影响是否因不同栽培条件而异尚不清楚。2011年利用中国稻田FACE(Free Air CO2Enrichment)系统平台,以敏感水稻品种汕优63为供试材料,二氧化碳设环境CO2浓度(Ambient)和高CO2浓度(Ambient+200μmol·mol-1),施氮量设低氮(15 g·m-2)和高氮(25 g·m-2),移栽密度设低密度(16穴·m-2)和高密度(24穴·m-2),研究了不同栽培条件下大气CO2浓度升高对杂交水稻产量形成的影响。结果表明:高浓度CO2对水稻抽穗期和成熟期没有影响,但使结实期株高显著增高(+7%);使单位面积穗数(+8%)和每穗颖花数(+19%)明显增多,进而使单位面积颖花量大幅增加(+29%)。高浓度CO2条件下穗数增多主要与最高分蘖数明显增加有关,而分蘖成穗率显著下降;穗型增大主要由单茎干重而非单位干重形成的颖花数增加所致。高浓度CO2环境下水稻结实能力呈增加趋势,其中平均粒重的增幅达显著水平。大气CO2浓度升高使水稻籽粒产量平均增加36%,其中在低氮低密度、低氮高密度、高氮低密度和高氮高密度条件下分别增加43%、46%、34%、23%。增施氮肥或增加移栽密度使水稻产量略有下降,但均未达显著水平。以上结果表明,高浓度CO2环境下杂交水稻因库容量增大导致产量大幅增加,调整施氮水平和移栽密度可在一定程度上改变这种肥料效应。

FACE下二氧化碳、施氮量、密度和锌肥对Ⅱ优084稻米锌浓度及有效性的影响

利用稻田FACE(FreeAirCO2Enrichment)平台,以Ⅱ优084为供试材料,主区CO2处理设置环境CO2浓度(AmbiGent)和高CO2浓度(比Ambient高50%)两个水平,裂区设置施氮量(15和25g/m2)、移栽密度(16和24株/m2,单本栽插)以及叶面施锌(0%和0.2%ZnSO4)处理,研究大气CO2浓度升高对超级稻精米和糙米锌浓度和有效性的影响.精米锌浓度、植酸含量以及植酸与锌的摩尔比均明显低于糙米.大气CO2浓度升高使精米和糙米锌浓度平均下降5%和7%,锌处理使对应部位锌浓度分别增加40%和63%,差异均达极显著水平,但施氮量或栽插密度处理对两部位锌浓度影响未达显著水平.CO2浓度和锌处理对精米和糙米的植酸含量均无显著影响,但增加施氮量和移栽密度使糙米植酸含量分别下降8%和6%,差异均达极显著水平.大气CO2浓度升高使精米和糙米中植酸与锌的摩尔比平均增加6%和7%,锌处理使对应部位植酸与锌的摩尔比分别下降28%和40%,增加施氮量和移栽密度使糙米中植酸与锌的摩尔比平均下降10%和7%.说明高浓度CO2环境下超级稻Ⅱ优084食用部位微量元素锌含量下降且生物有效性降低,但适当增加施氮量或移栽密度特别是结实期叶面喷施锌肥,可不同程度地改善该品种稻米的锌营养水平.

FACE条件下冬小麦的光合适应

利用开放式CO2浓度升高(Free Air Carbon dioxide Enrichment)系统平台,于冬小麦开花期、乳熟期对旗叶进行气体交换测量,根据光合模型计算光合参数,研究550μL.L-1CO2对冬小麦旗叶光合能力的影响。结果表明,无论是在冬小麦开花期还是乳熟期,FACE圈内的小麦叶片在短时间高CO2浓度下初始出现的光合速率增强逐渐减弱或消失,即FACE圈内的小麦叶片表现出对高CO2浓度的光合适应现象。低氮、常规施氮水平下均发现了小麦旗叶的光合适应现象,但是光合适应现象与施氮量没有显著的线性关系。另外,研究发现,FACE系统中,冬小麦旗叶的SPAD值和叶绿素含量降低,这可能是导致FACE系统中小麦叶片出现光合适应现象的原因。

近地层臭氧浓度升高对常规稻颖花形成的影响：FACE研究

FACE(free air gas concentration enrichment)研究使用标准的作物管理技术,在完全开放的大田条件下运行,代表了目前人类对未来大气环境的最好模拟。利用独特的大型稻田FACE平台,以典型的常规水稻品种武粳15(粳稻)和扬稻6号(籼稻)为供试材料,研究近地层臭氧(O3)浓度升高(比大气背景臭氧浓度平均增高26%)对常规水稻颖花形成的影响。结果表明:(1)高浓度O3对供试品种全穗以及一、二次枝梗颖化分化数均无显著影响;(2)高浓度O3使供试品种全穗和二次枝梗颖花退化数和退化率均显著增加,颖花退化增多是由于现存一次枝梗上二次枝梗大量退化而引起的二次颖花退化所造成;(3)颖花退化数在颖花分化数中所占比例很低,故高浓度O3对两供试品种全穗和一、二次枝梗颖花现存数以及稻穗构成均无显著影响。结合前报可知,选用常规水稻品种以及增施保花肥可能是未来近地层高浓度O3环境下稻作生产重要的适应措施。

开放式空气中CO_2浓度增高(FACE)对水稻生长和发育的影响

人类活动导致的大气和气候变化将极大地改变作物的生长环境,其中最大的一个变化就是大气二氧化碳(CO2)浓度的迅速上升:从工业革命前的平均270μmol/mol上升到目前的381μmol/mol,到2050年至少超过550μmol/mol。FACE(Free-air CO2 enrichment,开放式空气中CO2浓度增高)试验是目前评估未来高浓度CO2对作物生长和产量实际影响的最佳方法。水稻无疑是人类最重要的食物来源,迄今为止人类利用FACE技术开展水稻响应和适应的研究已有10a(19982008年)的历史。以生长发育为主线,首次系统综述了10a水稻FACE试验在该领域的研究成果,总结了FACE情形下高浓度CO2(模拟本世纪中叶大气CO2浓度)对主要供试水稻品种(小区面积大于4m2)光合作用、生育进程、地上部生长、地下部生长、物质分配、籽粒灌浆、产量构成以及倒伏性状等影响的研究进展,比较了FACE与非FACE研究之间以及中国和日本FACE研究(世界上唯一的两个大型水稻FACE研究)之间的异同点。根据研究进展以及当前的技术水平,文章最后提出了该领域的3个优先课题:(1)FACE情形下杂交稻生产力响应高于预期的生物学机制;(2)FACE情形下CO2与主要栽培措施的互作效应;(3)FACE情形下CO2与主要空气污染物臭氧的互作效应。这些响应的机理性解析将有助于从根本上减少人类预测未来粮食安全的不确定性,进而更加有效地制订出应对全球变化的适应策略。

开放式空气CO_2浓度增加(FACE)对水稻产量形成的影响及其与氮的互作效应

2001～2003年,在大田条件下以武香粳14号为供试品种,设计高、中、低氮处理,研究开放式空气CO2浓度增加(FACE)200μmolmol-1对水稻产量形成的影响及其原因。结果表明,FACE处理使水稻产量平均比对照增加12.8%,其中2001、2002和2003年增幅分别为10.8、14.1和13.6%,高、中、低氮处理的增幅分别为17.6、12.4、10.9%,均达到显著或极显著水平;FACE和氮处理对水稻产量的互作效应,2001、2002年达到显著水平,产量最高的处理组合为FACE×NN;FACE处理使水稻穗数平均比对照增加18.8%,每穗颖花数平均比对照减少7.6%,均达极显著水平;FACE处理使水稻生物产量平均提高16.2%,达极显著水平,使经济系数下降但未达到显著水平。进一步研究表明,FACE处理使水稻穗数极显著多于对照是因其分蘖发生速度快,最高分蘖数多所致,而不是其分蘖成穗率高的缘故;FACE处理使水稻每穗颖花数极显著少于对照是因其分化颖花的大量退化所致,而不是分化颖花数少的缘故。

FACE环境下不同秸秆与氮肥管理对稻田土壤产甲烷菌的影响

产甲烷菌是土壤中与甲烷产生和碳素循环有关的微生物菌群,大气CO2浓度升高可能对它们的数量产生影响。利用江都市小记镇的稻-麦轮作FACE平台,采用最大可能(MPN)法,在2004年水稻生长季研究了不同施肥情况(施常规氮量和低氮量)、不同秸秆还田情况(秸秆全还田、秸秆半还田、秸秆不还田)下,土壤中的产甲烷菌数量在大气CO2浓度升高条件下随时间的变化情况。结果表明,大气CO2浓度升高在秸秆全还田情况下对产甲烷菌数有明显的促进作用,在其他2种秸秆还田情况下,FACE与对照差异不显著。常氮处理仅在水稻生长初期促进产甲烷菌数,而在其他生长季不同氮肥处理之间无明显差异。总之,常氮处理产甲烷菌数量FACE比对照平均高104%～116%,低氮处理平均高101%～126%,进一步证实大气CO2浓度升高会促进稻田CH4的排放。

十年水稻FACE研究的产量响应

联合国政府间气候变化专业委员会(IPCC)最新报告预测20世纪中叶全球大气二氧化碳(CO2)浓度将由目前的381μmolmol-1至少上升到550μmolmol-1,CO2浓度不断升高将对世界粮食生产和安全产生深刻影响。与封闭和半封闭气室相比,FACE(FreeAir CO2 Enrichment,开放式空气中CO2浓度增高)技术平台,在完全开放的大田条件下运行,代表了人们对未来高CO2浓度环境的最好模拟。水稻是世界上最重要的粮食作物之一,在过去10a中(1998～2007年),全球有两个大型水稻FACE平台(直径12m)在运行,一个在温带地区的日本岩手,另一个在亚热带地区的中国江苏。以FACE研究为重点,系统收集和整理了高CO2浓度对水稻产量影响的研究进展,比较了FACE与各种气室研究结果的异同点,评估了CO2与生物(品种、病虫和杂草)和非生物因子(肥料、水分、温度和臭氧)的互作效应,提出了未来大气CO2浓度升高情形下水稻生产的适应策略,并讨论了该领域有待深入研究的方向。

开放式空气CO_2浓度增高(FACE)对水稻灌浆动态的影响

【目的】揭示大气CO2浓度升高对水稻籽粒灌浆动态的影响。【方法】利用农田开放式空气CO2浓度增高(FACE,free-air carbon dioxide enrichment)系统,以武香粳14为供试材料,CO2浓度设正常CO2(Ambient)和高CO2(FACE,Ambient+200μmol·mol-1)2个水平,施N量设低氮、中氮和高氮(150、250、350kg·ha-1)3个水平,测定各处理稻穗不同部位籽粒的灌浆进程,利用Richards方程拟合。【结果】(1)FACE处理明显提高了低氮水平实测最终米粒重,稻穗上、中、下部米粒增重分别为11.1%、10.9%和9.4%,全穗平均增重10.6%,而对中、高氮水平下粒重的影响较小;(2)FACE处理普遍提高了稻穗各部位籽粒灌浆的相对起始势;(3)FACE处理明显提高籽粒最大灌浆速率,低、中、高3种施氮条件下,全穗平均增幅分别为32.9%、36.9%和40.4%,稻穗上部籽粒增幅高于中、下部籽粒;同时明显提高了籽粒平均灌浆速率,低、中、高3种施氮条件下增幅分别为20.3%、25.8%和31.0%;(4)FACE处理总体上延迟了灌浆速率峰值出现的时间,最大灌浆速率时间的粒重增加,实灌时间缩短;从水稻籽粒灌浆阶段划分特征来看,FACE明显延长了灌浆前期持续时间,缩短了灌浆中期及后期持续时间。【结论】FACE处理提高了灌浆相对起始势、最大及平均灌浆速率,灌浆前期时间延长而灌浆中、后期时间缩短,总灌浆时间明显缩短,各粒位米粒重在低氮条件下明显增加而中、高氮条件下无明显变化。

FACE对武香粳14颖花分化和退化的影响

2001—2003年，利用我国唯一的农田开放式空气c02浓度增高（FACE）研究平台，研究大气c02浓度比对照高200μmol·mol^-1的FACE处理对水稻品种武香粳14颖花分化和退化的影响。FACE处理结果表明，每穗现存颖花数平均比对照少10．4～12．6朵，降幅为6．88％～8．49％，达极显著水平；对每穗颖花分化数和1次枝梗颖花退化数无显著影响，但使2次枝梗颖花的退化数和退化率显著高于对照；水稻每朵分化颖花所占有的抽穗期植株含N量和拔节至抽穗期的吸N量显著或极显著小于对照，使抽穗期茎鞘中可溶性碳水化合物含有率及其与植株含N率的比值显著或极显著高于对照；每朵分化颖花所占有的抽穗期植株含N量和拔节至抽穗期的吸N量与每穗颖花退化数均呈线性负相关，相关系数分别为-0．848^＊＊、-0．961^＊＊;抽穗期茎鞘中可溶性碳水化合物含有率及其和植株含N率的比值与每穗颖花退化数均呈线性正相关，相关系数分别为0．808^＊、0．831^＊。认为FACE处理降低水稻颖花形成期吸氮能力，使植株碳代谢增强、氮代谢减弱可能是其分化颖花大量退化和每穗颖花数少于对照的重要原因之一。