兰州大学机构库 >生命科学学院
根源信号调控下不同倍体小麦产量形成及株型塑性响应研究
Alternative TitleYield formation and plant type plasticity response under the the regulation of root-sourced signal in different ploidy wheat (Triticum aestivum L.)
桂妍雯
Subtype博士
Thesis Advisor熊友才
2021-05-31
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name理学博士
Degree Discipline生态学
Keyword小麦 株型 驯化 根源信号 产量形成 生物量分配 转运特性 库源关系
Abstract非水力根源信号(nHRS)和水力根源信号(HRS)是植物对干旱胁迫的重要响应,对旱地小麦的株型塑性、生物量的积累、转运和分配、水分利用、源库调节及产量形成起到关键调控作用,但其进化规律和调控机制仍然不是很清楚。基于此,本研究以根冠通讯理论为基础,选用进化路线上具有亲缘关系及驯化程度不同的14个小麦品种为试验材料,采用盆栽试验和大田试验相结合的方法,通过设置不同的水分梯度(其中盆栽控水试验设置充分供水、中度干旱胁迫、重度干旱胁迫三种水分条件,大田试验设置充分供水和干旱胁迫两种水分条件),测定了小麦的气体交换参数、株型、产量及产量组成因子、水分利用效率、生物量的积累、转运和分配、源库关系等指标,分析不同倍体小麦材料在根源信号调控下株型塑性、产量形成、生物量分配模式、水分利用效率、生物量的积累、转运及分配特性和库源关系的特征和差异,并对其响应机制进行研究和探讨。主要研究结果如下: (一)根源信号调控下不同倍体小麦株型的响应(盆栽控水试验) 1.采用盆栽控水试验,设置三个水分梯度,充分供水(CK ,80%FC)、中度干旱胁迫(50% FC)和重度干旱胁迫(30% FC),测量小麦的叶片相对含水量(LRWC)和气孔导度(Gs)。结果表明,与充分供水相比,在50% FC条件下,小麦的LRWC未发生显著变化,但Gs显著降低,表明植物启动非水力根源信号来响应干旱胁迫;在30% FC条件下,小麦的LRWC和Gs均显著降低,表明植物启动水力根源信号来响应更深程度的干旱胁迫。 2. 根源信号调控下小麦的株型结构发生变化。在nHRS调控下,所有倍体小麦叶面积、株高、节长、节粗、穗下节长/节总长的比值、分蘖数、穗长、穗粒数和根系重量均降低,上三叶叶夹角、叶开角、根冠比、冠层质量密度和叶片的长/宽增加,小麦的叶片变得细长;在HRS调控下,小麦上述株型指标的降低幅度或增加幅度均增加。不同倍体小麦对根源信号调控的响应方式存在差异,高倍体小麦的叶面积、有效分蘖数、小穗数、穗粒数、穗长和根系重量的降低幅度均小于二倍体小麦,而根冠比的增加幅度大于二倍体小麦。 (二)根源信号调控下不同倍体小麦产量形成、水分利用效率及生物量分配的响应(盆栽控水试验) 3. 根源信号调下所有倍体小麦的产量及其形成因子等指标均降低,但降低幅度存在差异。在nHRS调控下,二四六倍体小麦籽粒产量的下降幅度为45%、40%和36%;地上生物量的下降幅度为40%、36%和35%;收获指数的下降幅度为9.6%、5.0%和4.8%;单株粒数的下降幅度为51%、36%和33%;单株穗重的下降幅度为47%、38%和35%;单株小穗数的下降幅度为36%、33%和31%。在HRS调控下,二四六倍体小麦籽粒产量的下降幅度为69%、65%和65%;生物量的下降幅度均为65%;收获指数的下降幅度为16%、23%和22%;单株粒数的下降幅度为68%、72%和71%,单株穗重的下降幅度为69%、71%和70%;单株小穗数的降低幅度分别为68%、66%和65%。由此得出四倍体和六倍体小麦在nHRS调控下,籽粒产量及产量形成因子和收获指数的下降幅度低于二倍体小麦,在HRS调控下,三个倍体的下降率没有差异。因此在nHRS调控下,经过人工选择的四六倍体小麦的耐旱能力大于自然选择的二倍体小麦,当小麦启动HRS时,已经超过小麦的耐旱阈值,所以三个倍体之间无显著性差异。 4. 根源信号调控下小麦的水分利用效率降低,在nHRS调控下,二四六倍体地上生物量水分利用效率分别降低了2.4%、2.1%和1.8%;而籽粒产量的水分利用效率分别降低了8.0%、3.2%和2.8%。在HRS调控下,二四六倍体地上生物量水分利用效率分别降低了13.9%、16.2%和17.7%;而籽粒产量的水分利用效率分别降低了26.0%、31.9%和33.0%。在nHRS调控下,具有人工选择痕迹的高倍体小麦能够维持较高的水分利用效率,耐旱性较强;而在HRS调控下,高倍体小麦对干旱的耐受性会下降,从而导致水分利用效率的大幅度下降。 5. 根源信号调控下小麦的根冠比增加,四六倍体小麦的根冠比显著低于二倍体小麦。经异速生长分析,在CK 条件下,二四六倍体小麦地上生物量(Maboveground)与地下生物量(Mroot)之间的异速生长指数分别为1.31、0.68和0.69,四六倍体小麦的<1,二倍体小麦的>1;营养器官生物量(Mvegetative)与繁殖器官生物量(Mear)之间的异速生长指数分别为1.48、1.75和1.91,呈增加趋势。在nHRS调控下,四六倍体小麦的地上生物量(Maboveground)与地下生物量(Mroot)之间的为0.89和0.76,vegetative)与繁殖器官生物量(Mear)之间的为1.35,>1。结果表明随着驯化程度增加,高倍体小麦将更多的生物量分配至地上部分和繁殖器官,在根源信号调控下高倍体小麦依然能够较好的维持这种生物量分配格局。 (三)根源信号调控下不同倍体小麦生物量积累、转运和分配的响应(盆栽控水试验) 6. 根源信号调控下小麦的花前花后同化物积累能力降低,但会提高小麦对花前同化物的转运能力和及其对籽粒的贡献率。在nHRS调控下,二四六倍体小麦花前同化物积累量的减损率分别为28%、23%和19%;花后同化物积累量的减损率分别为46%、44%和34%;花前同化物花后转运量的增加率分别为6%、15%和31%;花前同化物花后转运率增加率分别为46%、53%和57%;花前同化物积累对籽粒的贡献率增加率分别为32%、34%和37%。在HRS调控下,二四六倍体小麦的花前同化物积累量的下降幅度分别为35%、29%和28%;花后同化物积累量的下降幅度分别为78%、63%和52%;花前同化物花后转运量的增加率分别为10%、19%和34%;花前同化物花后转运率增加率分别为70%、77%和84%;花前同化物积累对籽粒的贡献率增加率分别为57%、62%和65%。结果表明,高倍体小麦的花前花后同化物积累量降幅低于二倍体小麦,而花前同化物转运能力和花前同化物积累对籽粒的贡献率却高于二倍体小麦,说明高倍体小麦在逆境下对籽粒产量的补偿能力大于二倍体小麦,因此高倍体小麦在根源信号调控下依然能维持较高产量。 7. 根源信号调控下小麦生物量在各营养器官中的分配比发生变化。在nHRS调控下,四六倍体穗轴及颖壳中分配比例显著减少,茎中的分配比例显著增加,籽粒的分配比例没有显著差异;在HRS调控下,四六倍体小麦的籽粒分配比例下降。说明在nHRS调控下,经过人工选择的四六倍体小麦的耐旱能力大于自然选择的二倍体小麦,能够进行主动的防御策略,维持籽粒的形成;而当小麦启动HRS时,四六倍小麦采取了被动的防御策略,使籽粒产量降低。 (四)非水力根源信号调控下不同倍体小麦源库特性的响应(大田试验) 8. 非水力根源信号调控下小麦叶、鞘、茎的干重降低,单穗有效小穗数,单穗穗重、单穗粒数及单穗粒重均降低,且小麦的源库比发生改变,并影响源库调节。在非水力根源信号调控下,花后同化物积累量减少,而花前同化物花后转运量、转运率以及花前同化物积累对籽粒的贡献率增加,花前同化物能够缓冲源供应与库需求之间的矛盾,而高倍体小麦的这种缓冲能力较强,所以能够维持较高的籽粒产量,验证了盆栽控水试验的结论。 9. 在非水力根源信号调控下,随着倍体的增加,缩源减库处理下的叶、鞘、茎的干重呈现出先增加后降低的趋势,缩源处理下小麦叶、鞘、茎的干重降低,二四六倍体小麦叶、鞘、茎的下降幅度分别为18.5%、13.6%、23.4%;11.3%、5.3%、22.3% 和15.0%,8.4%、19.8%,均随倍体的增加呈现出先降低后增加的变化趋势,且六倍体小麦的下降幅度最大;减库处理下小麦叶、鞘、茎的干重增加,二四六倍体小麦叶、鞘、茎的增加幅度分别为12.4%、28.6%、7.2%;10.1%、33.7%、3.9%和11.1%、25.9%、6.4%,均随倍体的增加呈现出先增加后降低的变化趋势,且六倍体小麦的增幅最小。结果表明,由二倍体到六倍体驯化的过程中,小麦的源库比先增加后减小,呈现出先增源后扩库的形式,六倍体小麦的源库比最低。 10. 在非水力根源信号调控下,缩源减库处理下小麦的产量降低,且减库处理下的下降幅度均大于缩源处理。减库处理去除了一半的穗,减库处理下四倍体小穗数的下降率大于50%,二倍体和六倍体的下降率小于50%,且二倍体的下降率大于六倍体,说明四倍体小麦存在着一定的库限制,而二倍体和六倍体小麦均存在着一定的源限制,且六倍体小麦的源限制大于二倍体小麦。缩源处理使千粒重下降,下降幅度随着倍体的增加呈现先下降后上升的趋势;减库处理使千粒重上升,但并未增加至对照的两倍,说明不同倍体小麦均存在着不同程度的源限制和库限制。 本研究基于不同倍体小麦株型、产量形成、水分利用、生物量的积累、转运和分配及库源关系对根源信号的响应,得出在非水力根源信号调控下,小麦以积极主动的方式响应轻度干旱胁迫,在水力根源信号调控下,采取消极的被动的防御策略应对更深程度的干旱胁迫,且高倍体小麦在根源信号调控下仍然能够维持较好的株型结构和产量形成。本研究对根源信号调控下产量形成和株型塑性响应机制进行了较为系统的研究,研究结果既为抗旱节水育种与栽培技术提供理论依据,也为目前作物生态与系统进化领域提供了新的数据支撑。
Other AbstractNon-hydraulic root-source signals (nHRS) and hydraulic root-source signals (HRS) are important responses of plants to drought stress. They are important for plant plasticity, biomass accumulation, transportation and distribution, water use, source-sink regulation, and yield formation in dryland wheat. However,its evolutionary laws and regulatory mechanisms are still not very clear. Therefore, based on the theory of root-shoot communication, 14 wheat varieties with genetic relationship and different degrees of domestication along the evolutionary route were selected as the experimental materials. The pot experiment and field experiment were used to combine the method of setting different water gradient(In the potted water control experiment, three water conditions were set: adequatewater supply, moderate drought stress and severe drought stress;in the field experiment, two water conditions were set: adequatewater supply and drought stress).The gas exchange parameters, plant type, yield and yield component factors, water use efficiency, biomass accumulation,transportation and distribution, source-sink relationship and other indexes of wheat were measured.The characteristics and differences of plant type plasticity, yield formation, biomass allocation mode, water use efficiency, biomass accumulation, transport and distribution characteristics, and sink source relationship of different wheat materials under the regulation of root signal were analyzed and compared, and their response mechanisms were studied and discussed,the main research results obtained are as follows: Response of different ploidy wheat plant types to root signal regulation (water control experiment in pot) The relative water content (LRWC) and stomatal conductance (GS) of wheat were measured under three water gradients i.e. adequate water supply (CK, 80%FC), moderate drought stress (50% FC) and severe drought stress (30% FC). The results showed thatthe LRWC of wheat did not change significantly under 50% FC, but the Gs was significantly reduced compared with adequate water supply (CK, 80%FC), indicating that plants initiate non-hydraulic root signals in response to drought stress. Under 30% FC conditions, both LRWC and Gs of wheat were significantly reduced, indicating that the plant initiates hydraulic root signals as a kind of response to deeper drought stress. The plant type structure of wheat is changed under the regulation of root signal. Under the regulation of nHRS, all ploidy wheat leaf area, plant height, node length, the node diameter, the ratio of under-spike node length to total node length, tiller number, ear length, grain number per plant and root weight decreased slightly, with the increase of basal angle, opening angle, root-to-shoot ratio, canopy biomass density and leaf length/width ratio, wheat leaves become "slender";under the control of HRS. The above plant type indicators of wheat are greatly changed. Different ploidy wheats have different responses to root signal regulation. The reduction in leaf area, effective tiller number, spikelet number, grain number per spike, spike length, and root weight of high-ploid wheat was less than that of diploid wheat, while the root-shoot ratio was highly increased than that of diploid wheat. Response of yield formation, water use efficiency and biomass allocation of different ploidy wheat to root signal regulation (water control experiment in pot). The yield and formation factors of all ploidy wheat were decreased under the root signal regulation, but there were differences in the extent of reduction. Under the control of HRS, the reduction rates of grain yield of diploid, tetraploid and hexaploid wheat were 45%, 40% and 36%, respectively. While, the reduction rates of aboveground biomass was 40%, 36% and 35%;harvest index was 9.6%, 5.0% and 4.8%;grain number per plant were 51%, 36% and 33%;ear weight per plant were 47%, 38% and 35%;spikelet number per plant were 36%, 33% and 31%, respectively in diploid, tetraploid and hexaploid of wheat. Under the control of HRS, the grain yield of diploid, tetraploid and hexaploid wheat decreased by 69%, 65% and 65%;The biomass by 65% in all ploides;The harvest index by 16%, 23% and 22%;The grain number per plant by 68%, 72% and 71%, and ear weight per plant by 69%, 71% and 70%, respectively. The number of spikelets per plant decreased by 68%, 66% and 65%, respectively. It could be concluded that the decrease of grain yield, yield components and harvest index of tetraploid and hexaploid wheat under nHRS regulation was lower than that of diploid wheat. Under the regulation of HRS, there is no difference in the decrease rate of the three ploidy. and the decrease rate of the three ploidies are basically the same wheat under HRS regulation. Therefore, under the regulation of nHRS, the drought tolerance of artificially selected tetrahexaploid wheat is greater than that of naturally selected diploid wheat, and when wheat starts HRS, it has exceeded the drought tolerance threshold of wheat, so there is no difference between the three ploidy. The water use efficiency of wheat is reduced under the regulation of root signal. Under the control of nHRS, the WUE of aboveground biomass of diploid, tetraploid and hexaploid wheat was decreased by 2.4%, 2.1% and 1.8%, respectively, while the WUE of grain yield was decreased by 8.0%, 3.2% and 2.8%, respectively. Under the regulation of HRS, the WUE reduction rates of aboveground biomass of diploid, tetraploid and hexaploid wheat were 13.9%, 16.2%, and 17.7%, respectively, while the WUE reduction rates of grain yield were 26.0%, 31.9% and 33.0%, respectively. Under the regulation of nHRS, the high ploidy wheat with artificial selection trace could maintain high water use efficiency and strong drought tolerance, while under the regulation of HRS, drought tolerance of high-ploidy wheat would decrease, resulting in a significant decrease in water use efficiency. Root-shoot ratio of wheat increases under the regulation of root signal and the root-shoot ratio of tetraploid and hexaploid wheat was significantly lower than that of diploid wheat. According to allometry analysis, the allometric exponent (ɑ) of Maboveground vs Mroot decrease of diploid, tetraploid and hexaploid wheat under CK condition were 1.31, 0.68 and 0.69, respectively. It was observed that tetraploid and hexaploid wheat <1, diploid wheat >1;The allometric exponent between Mear vs Mvegetative of diploid, tetraploid and hexaploid wheat were 1.48, 1.75 and 1.91, respectively, showing an increasing trend. Under the control of nHRS, the values between Maboveground vs Mroot of tetraploid and hexaploid wheat were 0.89 and 0.76, <1;Under the control of HRS, the between Mear vs Mvegetative of hexaploid wheat was 1.35, >1. The results show that as the degree of domestication increases, high-ploid wheat will allocate more biomass to the above-ground parts and reproductive organs. High-ploid wheat can still maintain this biomass distribution pattern under the control of root signals. Responses of biomass accumulation, transportation and distribution of different ploidy wheat to root signal regulation (water control experiment in pot) The regulation of root signal decreased the capacity of assimilate accumulation pre-anthesis and post-anthesis, but increased the capacity of assimilate transport of pre-anthesisand its contribution rate to grain formation. Under the control of nHRS, the decreasing rates of pre-anthesis assimilate accumulation in diploid, tetraploid and hexaploid wheatwere 28%, 23% and 19%, respectively. The reduction rates of assimilate accumulation of post-anthesiswere 46%, 44% and 34%, respectively. The increase rates of post-anthesis transportation of pre-anthesis assimilate in diploid, tetraploid and hexaploid wheat were 6%, 15% and 31%, respectively. Post-anthesis transport rate of pre-anthesis assimilate increased by 46%, 53% and 57% in diploid, tetraploid and hexaploid, respectively. The contribution rate of pre-anthesis assimilate to grain yield increased by 32%, 34% and 37%, respectively. Under the control of HRS, the reduction rates of pre-anthesisassimilate accumulation were 35%, 29% and 28% and in assimilate accumulation of post-anthesiswere 78%, 63% and 52% in diploid, tetraploid and hexaploid, respectively. The increase rates of post-anthesis transportation of pre-anthesis assimilate were 10%, 19% and 34%, respectively. The post-anthesis transport rate of pre-anthesis assimilate increased by 70%, 77% and 84%, respectively. The contribution rate of pre-anthesis assimilate to grain yield increased by 57%, 62% and 65%, respectively. The results showed that with the increase of ploidy, the reduction rate of pre-anthesis and post-anthesis assimilates accumulation of high-ploid wheat was lower than that of diploid wheat, and the capacity of transportation of pre-anthesis and the contribution rate of pre-anthesis assimilates to grain is higher than that of diploid wheat, indicating that high ploid wheat has a greater ability to compensate grain yield under adversity than diploid wheat, so high ploid wheat can still maintain a higher yield under the regulation of root signals. The root signal regulation changed the allocation ratio of biomass accumulation in different vegetative organs of wheat. Under the regulation of nHRS, the allocation ratio of rachis and glumes in tetraploid and hexaploid wheat was significantly reduced, and the allocation ratio in stems increased significantly, and there was no significant difference in the allocation ratio of grains. Under the control of HRS, the allocation ratio of grains in tetraploid and hexaploid wheat decreased. Under the regulation of nHRS, the drought tolerance of artificially selected tetraploid and hexaploid wheat is greater than that of naturally selected diploid wheat, and can carry out active defense strategies to maintain the grains formation, and when wheat starts HRS, tetraploid and hexaploid wheat have adopted a passive defense strategy to reduce grain yield. Response of source-sink characteristics of different ploidy wheat under the control of non-hydraulic root signals (field experiment) The dry weight of leaf, sheath and stem, effective spikelet number per plant, ear weight per plant, grain number per plant and grain weight per grain were decreased by non-hydraulic root signal regulation, and the source-sink ratio of wheat was changed, and the source-sink regulation was affected. Under the control of non-hydraulic root signals, the accumulation of assimilates of post-anthesis decreases, while the post-anthesis transportation and post-anthesis transport rate of pre-anthesis assimilate and contribution rate of pre-anthesis assimilate to grain yield increases. pre-anthesis assimilation can buffer the contradiction between source supply and sink demand, and high-ploid wheat has a strong buffering capacity, so it can maintain a higher grain yield, which verifies the conclusion of the potted water control experiment. Under the regulation of nHRS, with the increase of ploidy, the dry weight of leaves, sheaths and stems under the treatment of defoliated and de-grainedshowed a trend of first increased and then decreased, and the dry weight of leaves, sheaths and stems of diploid, tetraploid and hexaploid wheat under the treatment of defoliated decreased, and the loss rates of leaves of diploid, tetraploid and hexaploid wheat were 18.5%, 13.6% and 23.4%, respectively. The loss rates of sheaths in three ploidies wheat were 11.3%, 5.3% and 22.3%, respectively. The loss rates of stems in three ploidies wheat were 15.0%, 8.4% and 19.8%, respectively. All showed a trend of decreasing first and then increasing with the increase of ploidy, and the decrease rate of hexaploid wheat was the largest. The dry weight of leaves, sheaths and stems increased under the treatment of de-grained. And the increase rates of leaves of diploid, tetraploid and hexaploid wheat were respectively were 12.4%, 28.6%, 7.2%, the increase rates of sheaths of diploid, tetraploid and hexaploid wheat 10.1%, 33.7%, 3.9% and the increase rates of stems of diploid, tetraploid and hexaploid wheat were 11.1%, 25.9%, 6.4%, all of which showed a trend of first increasing and then decreasing with the increase of ploidy, and the increase of hexaploid wheat the smallest. The results showed that in the process of domestication from diploid to hexaploid, the source-sink ratio of wheat first increased and then decreased, showing a form of first increasing source and then expanding sink. The source-sink ratio of hexaploid wheat was the lowest. Under the regulation of nHRS, the treatment of defoliated and de-grainedreduced the yield of wheat, and the decline under the treatment de-grainedwas greater than that of the treatment of defoliated. The de-grainedtreatment removed half of the ears. The reduction rate of the number of tetraploid spikelets under the de-grainedtreatment was greater than 50%, the reduction rate of diploid and hexaploid was less than 50%, and the reduction rate of diploid wasmorethan hexaploid wheat. It shows that tetraploid wheat has a certain sink imitation, while diploid and hexaploid wheat have certain source imitation , and the source limitation of hexaploid wheat is greater than that of diploid wheat. The defoliated treatment reduced the thousand-grain weight, and the decline showed a trend of first decrease and then increase with the increase of ploidy;the de-grained treatment increased the thousand-grain weight, but did not increase to twice that of the control, which indicated that different ploidy wheat had different degree of source limitation and sink limitation. Therefore, in order to improve the yield in future breeding, it is necessary to further increase the sink capacity while expanding the source, so as to reduce the limit of yield improvement. Based on the response of different ploidy wheat plant types, yield formation, water use, biomass accumulation, transportation and distribution, and sink-source relationships to root-source signals. It is concluded that under the regulation of non-hydraulic root-source signals, wheat takes a proactive approach in response to mild drought stress, under the regulation of hydraulic root signals, a passive defense strategy is adopted to deal with deeper drought stress, and high ploidy wheat can still maintain better plant structure and yield formation under the regulation of root signals. In this study, we systematically studied the response mechanism of yield formation and plant type plasticity under the regulation of root signals. The results of this study not only provide theoretical basis for drought resistance and water saving breeding and cultivation techniques, but also provide new data support for the current crop ecology and system evolution field.
Pages146
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/460170
Collection生命科学学院
Affiliation生命科学学院
First Author AffilicationSchool of Life Sciences
Recommended Citation
GB/T 7714
桂妍雯. 根源信号调控下不同倍体小麦产量形成及株型塑性响应研究[D]. 兰州. 兰州大学,2021.
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