【作者】 高波；

【导师】 王余龙； 杨连新；

【作者基本信息】 扬州大学 ， 作物栽培学与耕作学， 2022， 博士

【摘要】 全球大气二氧化碳(CO2)浓度持续升高是目前最主要的气候变化因子之一,通过促进水稻(Oryza sativa)的光合作用,CO2浓度升高将对水稻生长产生深刻影响。源库关系是作物栽培生理的热点问题之一,调节源库关系是否影响水稻产量和品质对高CO2浓度的响应尚不清楚。剪叶疏花是改变作物源库关系的常用手段之一,该方法通过人为减源或减库改变原有植株的源库关系,进而与对照植株进行比较分析。本研究于2017-2018年利用开放式CO2浓度升高平台(FACE,Free air CO2 enrichment),设置环境CO2浓度(Ambient)和高CO2浓度(增加200μmol·mol-1)两个水平,以常规稻武运粳27(WYJ27)和杂交稻甬优538(YY538)两个不同源库类型水稻为供试材料,于抽穗期设置对照(CK,不剪叶剪穗)、剪1叶(LC1,剪去剑叶)、剪3叶(LC3,剪去顶3叶)、剪1/3穗(SR1/3,间隔剪去稻穗1/3一次枝梗)和剪1/2穗(SR1/2,间隔剪去稻穗1/2一次枝梗)五个处理,通过大田群体试验,系统研究CO2浓度增高、减源疏库及其互作对水稻产量及构成因子、物质生产与分配、光合作用以及稻米品质和稻草饲用品质的影响及品种间差异,并从生长和光合等角度解释产量响应的部分生理原因,旨在为未来高CO2浓度环境下水稻生产策略的制定提供科学依据。主要结果如下:1.高CO2浓度使两供试品种单位面积籽粒产量平均增加18.8%**,其中WYJ27和YY538 平均分别增加 1 5.7%**和 21.8%**;两品种在 CK、LC1、LC3、SR1/3 和 SR1/2处理下平均分别增加1 7.0%**、20.5%**、26.1%**、16.7%**和15.4%**,其中剪叶处理水稻的增幅均大于对照或剪穗处理水稻,且均以剪3叶水稻增幅最大,这主要与高CO2浓度对剪叶水稻饱粒率和平均粒重的增幅较大有关。从源库处理本身看,与CK相比,LC1、LC3、SR1/3和SR1/2处理使籽粒产量平均分别降低5.7%+、43.1%**、24.9%**和39.1%**,剪叶使产量降低主要与饱粒率和饱粒重降低有关,而疏花使产量下降主要与稻穗明显变小有关。武运粳27稻穗不同部位籽粒产量性状对高CO2浓度和剪3叶处理的响应表明,与Ambient相比,高CO2浓度使对照和剪3叶水稻籽粒产量分别增加15.9%**和25.1%**;从稻穗不同部位看,强、中、弱势粒分别增加15.6%**、20.4%**、22.7%**,中、弱势粒的产量增幅更大主要与其饱粒率和平均粒重的增幅较大有关;与CK相比,剪3叶使强、中、弱势粒产量分别减少26.7%**、53.2%**、66.1%**,中、弱势粒的降幅均大于强势粒主要与饱粒率的降幅较大有关。2.高CO2浓度对两品种叶片干重没有影响,但茎鞘(+14.5%)和稻穗(+18.6%)干重显著增加,地上部生物量因此显著增加(+14.1%)。从不同源库处理看,高CO2浓度使CK、LC1、LC3、SR1/3和SR1/2处理水稻地上部生物量平均分别增加12.5%*、15.2%*、18.5%**、13.7%**和12.2%*,剪叶水稻的平均增幅大于对照或剪穗水稻;从源库处理本身看,与CK相比,LC1、LC3、SR1/3和SR1/2处理使两品种地上部生物量平均分别降低6.7%*、30.4%**、5.1%+和6.1%*。从物质分配看,高CO2浓度使叶片干重占比平均降低12.4%**,稻穗则增加2.9%**,茎鞘影响较小;从不同源库处理看,高CO2浓度使CK、LC1、LC3、SR1/3和SR1/2处理水稻叶片干重占比平均分别降低11.2%**、12.8%**、11.7%*、14.6%**和11.2%**,稻穗和茎鞘的影响多未达显著水平。与CK相比,LC1、LC3、SR1/3和SR1/2处理使茎鞘干重占比平均分别增加6.5%**、25.6%**、31.9%**和54.0%**,使穗部干重占比分别降低1.5%**、5.3%**、23.0%**和37.5%**,LC1和LC3处理使叶片干重占比分别降低10.3%**和43.3%**,SR1/3和SR1/2处理则使其分别增加15.6%**和20.8%**。CO2与LC3、SR1/3、SR1/2之间对茎鞘或稻穗干重占比有不同程度互作效应,源库处理与品种互作对各器官干重及其占比亦多有显著影响。3.与Ambient相比,高CO2浓度使水稻结实期倒一叶(CK、SR1/3和SR1/2处理水稻)净光合速率(Pn)和水分利用率平均分别增加9.3%**和19.4%**,气孔导度(Gs)、蒸腾速率(Tr)和气孔限制值平均分别降低11.3%**、7.0%*和17.5%**。高CO2浓度对结实期倒二叶(CK和LC1处理水稻)和倒四叶(CK和LC3处理水稻)Gs和Tr影响较小,使Pn多呈增加趋势,但不同处理Pn的响应差异很大:CK水稻倒二和倒四叶Pn均无显著变化,而LC1水稻倒二叶(+10.7%)和LC3水稻倒四叶(+18.9%)均显著增加,且LC1和LC3水稻顶部剩余叶片Pn在结实后期对高CO2浓度仍有较明显响应。从剪叶疏花处理本身看,与CK相比,SR1/3和SR1/2处理使倒一叶Pn平均分别降低5.7%**和8.5%**;相反,剪叶处理则使整个结实期剩余叶片Pn一致增加,其中LC3水稻倒四叶Pn平均增幅(30.0%**)明显大于LC1水稻倒二叶(15.7%**);两个剪叶处理使结实期剩余叶片Gs大增(LC1水稻倒二叶和LC3水稻倒四叶平均分别增加26.1%*和58.1%**),而两个剪穗处理使结实中后期剑叶Gs的降幅均在10%以上,前者利于水稻利用空气中增多的CO2浓度,后者则相反。4.与Ambient相比,高CO2浓度使水稻结实期叶片和茎鞘非结构性碳水化合物(NSC)浓度平均分别增加9.2%**和19.1%**,其中叶片增幅主要集中在结实后期,而茎鞘在整个结实期均有显著增加。从源库处理本身看,LC1和LC3处理使茎鞘NSC浓度较CK平均分别降低11.4%**和24.8%**,SR1/3和SR1/2处理则使其大幅增加108.6%**和197.5%**;叶片NSC浓度在LC1、SR1/3和SR1/2处理下分别增加5.7%*、8.6%**和18.6%**,LC3处理则使其呈降低趋势。从总氮(TN)浓度看,高CO2浓度使结实期叶片TN浓度极显著下降2.9%;剪叶处理有增加茎鞘TN浓度的趋势,而剪穗处理呈相反趋势。花后剪穗处理大幅增加结实期茎鞘NSC浓度,这可能对叶片光合作用产生反馈抑制,削弱叶片对高CO2浓度的响应,结实后期叶片TN浓度下降也可能是抑制光合响应的原因之一;相反,剪叶水稻NSC浓度降低而TN浓度增加可能利于增强剩余叶片对高CO2浓度的响应,减弱甚至消除光合适应现象。5.与Ambient相比,高CO2浓度使两品种出精率和整精米率平均分别降低1.3%*和1.5%*,使精米垩白粒率和垩白度平均分别增加21.9%**和28.7%**,增幅表现为YY538大于WYJ27,剪穗水稻大于剪叶水稻;高CO2浓度使最高黏度和崩解值平均分别增加2.4%**和4.8%**,消减值降低341.8%**,这与米饭食味测定结果一致(食味值+4.6%**、外观+3.3%**、黏度+2.8%**、平衡度+3.3%**和硬度-3.4%**);高CO2浓度使稻米蛋白质(-2.6%**)、S(-1.6%**)和Cu(-12.4%**)浓度极显著降低,使K浓度显著增加(+2.2%*),但Ca、Mg、P、B、Fe、Mn、Zn以及植酸浓度无显著变化。与CK相比,剪叶处理对加工品质影响较小,但剪穗使精米率和整精米率均显著增加;LC1和LC3使精米垩白粒率分别增加12.1%**和14.5%**,垩白度分别增加22.7%**和35.7%**,而SR1/3和SR1/2处理则使垩白粒率分别降低31.9%**和60.4%**,垩白度分别降低44.4%**和73.9%**;剪穗处理使精米直链淀粉浓度显著降低,剪叶的影响则因品种而异;剪叶疏花处理使YY538崩解值和消减值均降低,但WYJ27响应较小;剪叶疏花处理使WYJ27米饭食味值均增加,而YY538变化较小;多数情况下,剪叶剪穗处理使稻米蛋白质和矿质元素浓度呈增加趋势。CO2与品种、源库处理间互作对稻米品质指标多无显著影响,但源库处理与品种间存在较多互作效应。6.与Ambient相比,高CO2浓度使成熟期稻草中可溶性糖、淀粉和NSC浓度平均分别增加11.1%**、4.1%和7.2%**,其中均以茎鞘增幅较大,叶片则有所降低;高CO2浓度使稻草粗蛋白(-5.3%**)、S(-5.9%*)、Cu(-7.8%+)、Mn(-14.8%**)浓度均降低,P浓度增加(+5.8%**),但Ca、K、Mg、Fe、Zn、B浓度无显著影响。与CK相比,LC1和LC3处理使稻草NSC浓度平均分别降低24.6%**和53.0%**,SR1/2和SR1/3则使之分别增加74.0%**和100.9%**;LC3使稻草粗蛋白累积量平均降低29.8%**,而SR1/3和SR1/2使之分别增加25.9%**和41.7%**;剪叶处理使稻草矿质元素浓度多呈增加趋势,剪穗则趋势相反(Ca、K、B和Zn浓度降幅均超10%)。CO2与品种、源库处理间对稻草饲用品质多无显著互作,但源库处理与品种间多有显著互作效应。综上所述,大气CO2浓度升高200 μmol·mol-1显著增加水稻产量,但同时降低稻米加工、外观和营养品质(蛋白质、S、Cu浓度尤其值得关注),食味品质则有变优趋势,稻草饲用品质略有降低。剪叶和疏花处理均使水稻减产,使稻米蛋白质和矿质元素浓度多呈增加趋势,而精米垩白的变化因处理而异(剪叶增加垩白,剪穗反之)。人为改变源库关系(剪叶疏花)未明显影响稻米食用品质和稻草饲用品质对高CO2浓度的响应,但降低源库比(剪叶)可增强剩余叶片光合能力的响应而提升产量增幅,剪穗则反之。可见,未来高CO2浓度环境下通过减源扩库(如控制无效分蘖、选育大库容品种、增施促花肥)等农艺措施降低源库比,有望进一步挖掘水稻产量响应的潜力,但这还需更多FACE试验的验证。更多还原

【Abstract】 The increasing atmospheric carbon dioxide(CO2)is one of the most important climate change factors,which will have a profound impact on rice(Oryza sativa)growth by promoting photosynthesis.Source-sink relationship is one of the hot issues in crop cultivation physiology.However,it is unclear whether regulating source-sink relationship affects the responses of rice yield and grain quality to elevated CO2.Cutting off leaves or removing spikelets are commonly used methods to study the source-sink relationship of crops.The original source-sink relationship of rice could be artificially changed by reducing the source and/or sink at the heading stage and then compared with the control plants in these methods.We grew japonica cultivar Wuyunjing 27(WYJ27)and hybrid cultivar Yongyou 538(YY538),which are widely used in production,under ambient CO2 concentration(aCO2)and elevated CO2 concentration(eCO2,200 μmol·mol-1 higher than aCO2)in a free air CO2 enrichment(FACE)facility in 2017-2018.At heading stage,five source-sink treatments were set by cutting off the flag leaf(LC1)and the top three leaves(LC3),removing one branch in every three branches of a panicle(SR 1/3)and one branch in every two branches of a panicle(SR1/2),in the control(CK),there was no leaf-cutting or spikelet-removal.In order to investigate the effects of eCO2 and sourcesink treatments on rice yield formation,dry matter production and distribution,photosynthetic capacity of leaves in different positions and quality traits,and the response of rice yield to source-sink treatment and eCO2 was explained from the perspective of photosynthesis.The purpose of this study was to provide a scientific basis for the development of rice production strategies under high CO2 concentration in the future.The main results were as follows:1.Compared with ambient,eCO2 increased the grain yield per unit area of the two varieties by 18.8%**on average,in which WYJ27 and YY538 increased by 15.7%**and 21.8%**,and crops under CK,LC1,LC3,SR1/3,and SR1/2 treatments were significantly increased by 17.0%**,20.5%**,26.1%**,16.7%**and 15.4%**,respectively.For both varieties,the increase rates of leaf-cutting crops were higher than those of the control or spikeletremoval crops,and the LC3 crops had the largest increase,and this was mainly related to the greater increase of grain filling rate and average grain weight of rice by eCO2.In terms of source-sink treatments,compared with control crops,LC1,LC3,SR1/3 and SR1/2 treatments reduced grains yield by 5.7%+,43.1%**,24.9%**and 39.1%**,respectively.For leaf-cutting crops,the decrease of grain yield was mainly related to the decrease of grain filling rate and grain filling weight,while for spikelet-removal crops that was mainly due to the decrease of spikelet per panicle.Further study on the effects of eCO2 and LC3 treatment on grain yield of WYJ27 showed that,compared with ambient,the grain yield of control and LC3 crops increased by 15.9%**and 25.1%**under eCO2;and in terms of different grain positions,eCO2 increased the yield of superior,medium,and inferior spikelet by 15.6%**,20.4%**,22.7%**,respectively.The increase of grain yield of medium and inferior spikelet was higher than that of superior spikelet,which was mainly related to the increase of grain filling rate and average grain weight.Compared with CK,LC3 reduced the yield of superior,medium and inferior spikelet grain yields by 26.7%**,53.2%**and 66.1%**respectively.The decrease of medium and inferior spikelet grain was larger than that of superior grain,which was mainly related to the decrease of grain filling rate of medium and inferior spikelet grain caused by LC3 treatment.2.The eCO2 had no effect on leaf dry weight,but significantly increased dry weight of stem(14.5%)and panicle(18.6%),resulting in a significantly increase in above-ground biomass(14.1%),and the above-ground biomass of crops under CK,LC1,LC3,SR1/3 and SR1/2 treatments increased by 12.5%*,15.2%*,18.5%*,13.7%**and 12.2%*,respectively,and.the average increase of leaf-cutting crops was greater than that of control or spikeletremoval crops.Compared with CK,LC1,LC3,SR1/3 and SR1/2 treatments reduced aboveground biomass by 6.7%*,30.4%*,5.1%+,and 6.1%*,respectively.In terms of matter distribution,eCO2 decreased dry weight ratio of leaf by 12.4%**and increased that of spikelet by 2.9%**,while it had no effect on that of stem.The dry weight ratio of leaves under CK,LC1,LC3,SR1/3 and SR1/2 treatments decreased by 11.2%**,12.8%**,11.7%**,14.6%**and 11.2%**,respectively,while the dry weight ratio of panicle and stem was not affected by eCO2.Compared with CK,the LC1,LC3,SR1/3 and SR1/2 treatments increased dry weight ratio of stem by 6.5%,25.6%,31.9%,and 54.0%,and decreased that of spikelet by 1.5%**,5.3%**,23.0%**,and 37.5%**,respectively;LC1 and LC3 treatments reduced the dry weight ratio of leaves by 10.3%**and 43.3%**,while SR1/3 and SR1/2 treatments increased it by 15.6%**and 20.8%**,respectively.Variety interactions were observed on dry weight ratio of stem or panicle between CO2 and LC3 or SR1/3 or SR1/2,and many significant interactive effects on dry weight or dry weight ratio of rice organs were observed between source-sink treatment and variety.3.Compared with ambient,eCO2 significantly increased net photosynthetic rate(Pn)and water use efficiency by 9.3%**and 19.4%**,and decreased stomatal conductance(Gs),transpiration rate(Tr)and stomatal limit decreased by 11.3%**,7.0%*and 17.5%**of the flag leaves in CK,SR1/3 and SR1/2 crops at filling stage on average.The eCO2 increased Pn of the second leaves(CK and LC1 crops)and fourth leaves(CK and LC3 crops)by 5.4%and 10.1%on average,respectively,with no significant effect on CK,while the second leaf of LC1 crops increased by 10.7%*and the fourth leaf of LC3 crops increased by 18.9%**on average.In addition,Pn of remaining leaves of LC1 and LC3 crops significantly increased at the later stage of filling under eCO2,with no effect on Gs and Tr.There were different degrees of interactions between CO2 and source-sink treatments on Pn of the second and fourth leaves.Compared with CK,SR1/3 and SR1/2 treatments reduced Pn of the flag leaves by 5.7%**and 8.5%**,respectively.On the contrary,the leaf-cutting treatment significantly increased the Pn of the remaining leaves during the whole grain filling stage,in which LC1 increased the Pn of the second leaves by 15.7%**,LC3 increased the Pn of the fourth leaves by 30.0%**on average.The leaf-cutting treatments significantly increased the Gs of remaining leaves at the filling stage(the second leaves of LC1 crops and the fourth leaves of LC3 crops increased by 26.1%*and 58.1%**on average),while spikelet-removal treatments significantly decreased the Gs of the flag leaves at the middle or late filling stage by more than 10%.The former was beneficial for rice to use the increased CO2 concentration,while the latter was contrary.4.Compared with ambient,the eCO2 increased non-structural carbohydrate(NSC)concentration in leaf and stem by 9.2%**and 19.1%**,respectively,during the filling stage,with the increase of leaf mainly in the late filling stage,but significantly increased NSC in stem during the whole filling stage.Compared with CK,LC1 and LC3 treatments reduced NSC concentration by 11.4%**and 24.8%**,while SR1/3 and SR1/2 treatments increased it by 108.6%**and 197.5%**,respectively;the leaf NSC concentrations increased by 5.7%*,8.6%**and 18.6%**under LC1,SR1/3 and SR1/2 treatments,respectively,while decreased under LC3 treatment.In terms of nitrogen concentration,eCO2 significantly decreased leaf nitrogen concentration(-2.9%)at filling stage,and leaf-cutting treatments tended to increase stem nitrogen concentration,while spikelet-removal treatments tended to reverse.The spikelet-removal treatments after anthesis significantly increased th e NSC concentration in stem during filling stage,which may have feedback inhibition on leaf photosynthesis and weaken leaf response to eCO2.In addition,the decrease of leaf nitrogen concentration at late filling stage may also be one of the reasons for inhibiting photosynthetic response.On the contrary,the decrease of NSC and the increase of nitrogen concentration by leaf-cutting treatments during filling stage may enhance the photosynthetic response of remaining leaves to eCO2,and weaken or even eliminate the photosynthetic adaptation.5.Compared with ambient,eCO2 reduced the milled rice percentage and the head rice percentage of the two varieties by 1.3%*and 1.5%*on average,and increased the chalkiness grain percentage and chalkiness degree of milled rice by 21.9%**and 28.7%**,respectively,the increase rate of YY538 was larger than that of WYJ27,and those of crops under spikeletremoval treatments were larger than those under leaf-cutting treatments.The eCO2 increased the maximum viscosity and breakdown value by 2.4%**and 4.8%**,respectively,and decreased the setback value by 341.8%**on average.These were consistent with the determination results of cooked rice(eating value+4.6%**,appearance+3.3%**,stickiness+2.8%**,balance+3.3%**,and hardness-3.4%**).The eCO2 significantly decreased the concentrations of protein(-2.6%**),(-1.6%**)and Cu(-12.4%**),and significantly increased K(+2.2%*)concentration,while there were no significant changes on Ca,Mg,P,B,Fe,Mn,Zn and phytic acid concentrations.Compared with CK,leaf-cutting treatments had little effect on processing quality,while.spikelet-removal treatments-significantly increased both milled rice percentage and the head rice percentage;LC1 and LC3 increased the chalkiness grain percentage by 12.1%**and 14.5%**,and increased chalkiness degree by 22.7%**and 35.7%**,respectively,while SR1/3 and SR1/2 decreased the chalkiness grain percentage by 31.9%**and 60.4%**,and decreased chalkiness degree by 44.4%**and 73.9%**,respectively.Spikeletremoval treatments significantly reduced the amylose content of milled rice,while the effects of leaf cutting varied with varieties.Leaf-cutting and spikelet-removal treatments reduce both breakdown and setback values of YY538,while no effect was observed in that of WYJ27.Both leaf-cutting and spikelet-removal treatments increase the taste values of WYJ27,while no significant changes were observed on YY538.In most cases,the concentrations of protein and elements were increased by leaf-cutting and spikelet-removal treatments.Most interactions among CO2,varieties and source-sink treatments had no significant effect on rice quality indexes,but there were many interactions between source-sink treatments and varieties.6.Compared with ambient,the concentrations of soluble sugar,starch and NSC in rice straw at maturity increased by 11.1%**,4.1%**and 7.2%**,respectively,with a larger increase in stem and a decrease in leaves.The concentrations of crude protein(-5.3%**),S(-5.9%*),Cu(-7.8%+),Mn(-14.8%**)decreased and P(+5.8%**)increased under eCO2,while Ca,K,Mg,Fe,Zn and B was not affected.Compared with CK,LC1 and LC3 treatments reduced the concentration of NSC by 24.6%**and 53.0%**,SR1/2 and SR1/3 increased it by 74.0%**and 100.9%**;LC3 reduced the absorption of crude protein by 29.8%**,SR1/3 and SR1/2 increased it by 25.9%**and 41.7%**,respectively.The concentrations of mineral elements in rice straw were increased by leaf-cutting treatments,while those of Ca,K,B and Zn were decreased by more than 10%under spikelet-removal treatments.There was no significant interaction between CO2 and variety or source-sink treatment on straw feeding quality,while significant interactions between source-sink treatments and varieties were observed.In conclusion,increasing atmospheric CO2 concentration by 200 μmol·mol-1 significantly increased rice yield,but decreased processing,appearance and nutritional quality of rice(protein,S and Cu concentrations were particularly noteworthy),while improved the taste quality;straw feeding quality was slightly decreased.Both leaf-cutting and spikelet-removal treatments reduced grain yield,but had little effect on processing and eating quality,and increased protein and element concentrations,while had different effects on chalkiness of milled rice(leaf-cutting treatments increased chalkiness,while spikelet-removal treatments decreased it).Artificial changes in source-sink relationship(leaf-cutting or spikelet-removal)did not significantly affect the response of rice quality to eCO2,however,reducing source-sink ratio enhanced the response of photosynthetic capacity of remaining leaves and increased yield,while spikelet-removal showed the opposite.The fertilizer effect of eCO2 can be further utilized by reducing the source-sink ratio of rice via artificial measures such as reducing the source-sink ratio and expanding the sink(e.g.controlling ineffective tillering,breeding varieties with large sink capacity and increasing flower fertilizer application)in the future.更多还原