苜蓿种子空间诱变生物学效应研究初报(英文)

[Objective] The study aimed to understand the mutagenic effects of space flight on alfalfa seeds.[Method] Seeds of three lines of alfalfa were carried into orbit by the satellite ’Shijian-8’ for space fight,the indices including seed germination rate,plant height and growth rate,were measured after the seeds been retrieved.[Result] Remarkable mutagenic effects occurred on the flight seeds,which were mainly presented by abnormal cotyledon,extended variation range of plant height and growth rate.Nineteen plants with increased plant height were preliminarily screened from the T0 progenies,but whether the mutated trait could inherit should be confirmed in further study.Three flight lines of alfalfa are different in the percentages of abnormal cotyledon(10%-18%),variation range of plant height(increased 30%-150% compared to control),selected plant number with increased plant height(5-7 plants),suggesting that differences exits between the three lines in mutation efficiency.[Conclusion] Valuable mutated materials could be obtained by space flight and applied in modern agriculture.     

Preliminary Study on the Mutagenic Effects of Space Flight on Alfalfa Seeds

[Objective] The study aimed to understand the mutagenic effects of space flight on alfalfa seeds.[Method] Seeds of three lines of alfalfa were carried into orbit by the satellite 'Shijian-8' for space fight,the indices including seed germination rate,plant height and growth rate,were measured after the seeds been retrieved.[Result] Remarkable mutagenic effects occurred on the flight seeds,which were mainly presented by abnormal cotyledon,extended variation range of plant height and growth rate.Nineteen plants with increased plant height were preliminarily screened from the T0 progenies,but whether the mutated trait could inherit should be confirmed in further study.Three flight lines of alfalfa are different in the percentages of abnormal cotyledon(10%-18%),variation range of plant height(increased 30%-150% compared to control),selected plant number with increased plant height(5-7 plants),suggesting that differences exits between the three lines in mutation efficiency.[Conclusion] Valuable mutated materials could be obtained by space flight and applied in modern agriculture.     

卫星搭载对紫花苜蓿当代植株生物量的影响(英文)

[Objective] The aim of this study was to investigate the effect of space flight factors on plant biomass in the generation of alfalfa carried by the satellite.[Method]Seeds from three lines of alfalfa were carried by the seed-breeding satellite Shijian-8.After the satellite returned to the ground,stem diameter,primary branch number and current-year individual biomass of alfalfa were studied.[Result]After space flight,primary branch number and current-year individual biomass of alfalfa increased significantly,while the stem diameter had no significant change.Using the value over(the mean value of control + three standard deviation)as a criterion to screen,the variants with enlarged stem diameter,increased primary branch number and individual biomass was two,five and twelve respectively.[Conclusion]The obtained variants can be used in the variety improvement of alfalfa and its new variety breeding,but whether its favorable variation can inherit stably to the progenies needs further study.     

A Comparative Study on Mutagenic Effects of Space Flight and Irradiation of γ-rays on Rice

The experiment was conducted to study the mutagenic effects of space environment on seedling growth in M1 generation and plant height and heading date in M2 generation in rice. Two types of lines of growth promotion （GP） and growth suppression （GS） were selected from the recombinant inbred lines （RILs） derived from a cross between a sensitive japonica Lemont and a nonsensitive indica Teqing to compare the mutation frequency and mutagenic efficiency for plant height and heading date in the M2 generation. Space environment resulted in 34.9% higher seedling height （SH） in the GP group than in the control, and 39.1% lower in the GS group than in the control, and there was no difference in seed fertility （SF） between the two groups. In M2, mutants of plant height and heading date can be induced by space treatment in both the two groups with lower mutation frequency and mutagenic efficiency in the GP group than in the GS group. There were no significant differences in the physiological damages in M1 between the two groups after γ-rays irradiation treatment. Mutation frequency and mutagenic efficiency of heading date in M2 were higher in the GS group than in the GP group, and the opposite was true for mutagenic efficiency of plant height although the mutation frequency varied between the two groups. The mutation frequencies of plant height and heading date induced by space environment were obviously lower than those by γ-rays irradiation, but the mutagenic efficiency was the opposite for most of the traits. For the GP and GS of seedlings induced by space environment, the GS had higher mutation frequency and mutagenic efficiency for plant height and heading date than the GP in M2.     

Calcium Addition Affects Germination and Early Seedling Growth of Sweet Sorghum under Saline Conditions

[Objective] This study aimed to determine the interactive effects of supplemental Ca amendment and salinity on germination of sweet sorghum seeds in saline solution culture medium,and investigate the effects of different combinations of Na/Ca ratio in saline soils on the early growth of sweet sorghum plants.[Method] A germination test and a greenhouse pot experiment were conducted to assess the interactive effects of calcium addition to culture medium on the germination and seedling growth of sweet sorghum(Sorghum saccharatum Moench) in saline soils with a range of Na/Ca ratios.In the germination test,seeds were treated with different combinations of five calcium levels [0,5,10,15,and 20 mmol/L Ca(NO 3) 2 ] and five salinity levels(0,50,100,150,and 200 mmol/L NaCl).In the greenhouse experiment,seeds were sown in potting soils containing 3 salinity levels(2.3,4.7 and 7.0 dS/m) and three Na:Ca ratios(10:0,10:1,and 5:1).[Result] In the germination test,Ca addition at 5 mmol/L promoted germination by 5.5%,9.9%,and 17.0% at the 3.4,6.7 and 10.1 dS/m salinity levels.The higher Ca level(10 mmol/L) also increased germination by 9.1% and 7.8% at the 3.4 and 6.7 dS/m salinity levels.Then even higher Ca addition at 15 and 20 mmol/L appeared to promote germination when culture media had high salinity(10.1 and 13.4 dS/m).In the greenhouse pot experiment,saline soil amended with supplemental Ca at the 2.3 and 4.7 dS/m salinity levels significantly promoted early seedling growth,with an increase of 6.8% to 28.2% in plant height and 14.3% to 67.9% in whole plant weight.From 28 to 42 d after seeding,the relative growth of seedling was increased by Ca addition,with a reduction of 49.5% to 66.0% in plant height and 4.8% to 61.9% in whole plant weight.From 42 to 56 d after seeding,however,the relative growth of seedling was significantly inhibited by Ca amendment.[Conclusion] Results of this study indicate that appropriate supplemental Ca could improve sorghum germination and early seedling growth in saline soils.     

QTL consistency for agronomic traits across three generations and potential applications in popcorn

Favorable agronomic traits are important to improve productivity of popcorn. In this study, a recombinant inbred line(RIL) population consisting of 258 lines was evaluated to identify quantitative trait loci(QTLs) for nine agronomic traits(plant height, ear height, top height(plant height subtracted ear height), top height/plant height, number of leaves above the top ear, leaf area, stalk diameter, number of tassel branches and the length of tassel) under three environments. Meta-analysis was conducted then to integrate QTLs identified across three generations(RIL, F2:3 and BC2F2) developed from the same crosses. In total, 179 QTLs and 36 meta-QTLs(m QTL) were identified. The percentage of phenotypic variation(R2) explained by any single QTL varied from 3.86 to 28.4%, and 24 QTLs with contributions over 15%. Nine common QTLs located in the same or similar chromosome regions were detected across three generations. Five meta-QTLs were identified including QTLs in three independent studies. Seven important m QTLs were composed of 11–26 QTLs for 4–7 traits, respectively. Only 11 m QTLs were commonly identified in the same or similar chromosome regions across agronomic traits, popping characteristics(popping fold, popping volume and popping rate) and grain yield components(ear weight per plant, grain weight per plant, 100-grain weight, ear length, kernel number per row, ear diameter, row number per ear and kernel ratio) by meta-QTL analysis. In conclusion, we identified a list of QTLs, some of which with much higher contributions to agronomic traits should be valuable for further study in improving both popping characteristics and grain yield components in popcorn.     

Effects of Mutagens on Antioxidant Enzymes Activity and Cold Resistance of Alfalfa

This study aimed to solve the issues in safe wintering of alfalfa in the north of China. The~(60)Co-γ rays, ultraviolet and EMS were used to mutagenize seeds of 4 cultivars of alfalfa to investigate the effects of mutagens on antioxidant enzymes activity and cold resistance of alfalfa. The results showed that after the mutagenic treatment, the activity of the three kinds of antioxidant enzymes basically showed upward trends.~(60)Co-γ radiation increased the activity of SOD; ultraviolet radiation decreased the activity of SOD; and low-concentration EMS promoted and high-concentration EMS inhibited the activity of SOD. The activity of POD and CAT decreased with the increased radiation dose of~(60)Co-γ, but increased with the increased radiation dose of ultraviolet. The effects of EMS treatment on the activity of POD and CAT differed among different alfalfa cultivars. The concentration of MDA reduced under 30-min, 60-min ultraviolet treatment and 0.4% EMS treatment. According to the subordinate function values of various indices, it could be concluded that 150 Gy of~(60)Co-γ radiation, 90 min of ultraviolet radiation, and 0.4% of EMS were more conducive to improving the cold resistance of alfalfa. This study will provide a theoretical basis for the research on adaptability and cold resistance of alfalfa in rigid cold region and a technical reference for the breeding of high-yield, highquality and cold-resistant alfalfa cultivars.     

Breeding Technology of eui-hybrids of Rice

Induced mutants of elongated uppermost internode (eui) were directly obtained after irradiation on maintainer (B) and restorer (R) lines of hybrid rice. CMS lines(A) with eui (referred to as eA), restorer lines with eui (referred to as eR) as well as hybrid rice with eui gene (referred to as e-hybrids)were developed. The results showed that the eui mutation frequency averaged 0.10‰ at a range of 0.02‰ - 0.47‰,varying with applied dosage and mutated materials. Genetic diversities of eui stock, and a new eui gene, temporarily designated as eui2(t), was identified. eA lines have a significantly elongated uppermost internode causing better panicle exsertion and possessing higher outcrossing potential. e-hybrids increased plant height by 3 - 10 cm and headed 2 - 3 days earlier, as well as showed greater grain weight resulting in higher yield potential than that of corresponding original hybrids. The technology systems without GA3, a few of using GA3 in hybrid rice seed production, and the establishment of e-hybrid rice breeding system were also discussed in this paper.     

冬凤兰非共生萌发和低温离体保存（英文）

[Objective] The aim of the research was to establish asymbiotic germination and low-temperature in vitro conservation technique system of Cymbidium dayanum by using plant tissue culture technique to realize its rapid propagation and long-term conservation in vitro.[Method] With mature seeds of C.dayanum as explants,different media were selected to establish asymbiotic germination technique system.With protocorms as materials,conservation,resumptive proliferation and plant regeneration conditions were selected to establish low-temperature in vitro conservation technique system preliminarily.[Result] Mature seeds of C.dayanum could germinate after cultured 90 days on MS media as well as "Hyponex 1" media.The germination rate reached more than 98%.Protocorms inoculated in "Hyponex 1" media could be conserved continuously at 5 ℃ in dark for more than 18 months and the survival rate could reach 90%.Conserved protocorms could realize resumptive proliferation culture both on 1/2 MS and "Hyponex 1" media.The seedling-strengthening and rooting media were 1/2 MS media.[Conclusion] This research provided practical basis for in vitro conservation and rapid propagation of C.dayanum germplasm resource.     

Heterotic loci identified for plant height and ear height using two CSSLs test populations in maize

Heterosis is an important biological phenomenon, and it has been used to increase grain yield, quality and resistance to abiotic and biotic stresses in many crops. However, the genetic mechanism of heterosis remains unclear up to now. In this study, a set of 184 chromosome segment substitution lines(CSSLs) population, which derived from two inbred lines lx9801(the recurrent parent) and Chang 72(the donor parent), were used as basal material to construct two test populations with the inbred lines Zheng 58 and Xun 9058. The two test populations were evaluated in two locations over two years, and the heterotic loci for plant height and ear height were identified by comparing the performance of each test hybrid with the corresponding CK at P0.05 significant level using one-way ANOVA analysis and Duncan's multiple comparisons. There were 24 and 29 different heterotic loci(HL) identified for plant height and ear height in the two populations at two locations over two years. Three HL(hlPH4a, hlPH7c, hlPH1b) for plant height and three(hlEH1d, hlEH6b, hlEH1b) for ear height were identified in the CSSLs×Zheng 58 and CSSLs×Xun 9058 populations as contributing highly to heterosis performance of plant height and ear height across four environments. Among the 29 HL identified for ear height, 12 HL(41.4%) shared the same chromosomal region associated with the HL(50.0%) identified for plant height in the same test population and environment.     

苜蓿种子空间诱变生物学效应研究初报

[目的]了解苜蓿种子空间诱变的生物学效应。[方法]3个品系的苜蓿种子搭载"实践八号"育种卫星飞行,返地后,对其种子出苗率、株高及生长速度等指标进行测试。[结果]卫星搭载对苜蓿种子有显著的诱变效应,主要表现在子叶畸变、株高变异范围和生长速度等方面。通过初步筛选,在搭载当代获得了高株变异,但该变异是否可遗传还需进一步研究确认。搭载的3个品系在子叶畸变率(10%~18%)、株高变异范围(比对照增加30%~150%)、入选变异高株数(5~7株)等方面不同,说明3个品系的搭载效率存在差异。[结论]通过空间诱变可获得有价值的变异材料,服务于现代农业。     

卫星搭载对紫花苜蓿二代种子诱变效应的研究

[目的]探寻空间诱变环境对苜蓿搭载二代种子的影响,为苜蓿诱变育种提供理论基础。[方法]2006年9月,三个品系的苜蓿干种子通过＂实践八号＂育种卫星进行空间搭载。返地后,经过地面种植,对其二代种子千粒重、发芽率、硬实种子数和苗重指标进行测试。[结果]与地面对照相比,搭载种子的千粒重增加了5%～9%。发芽试验结果表明,搭载后苜蓿二代种子发芽率、种苗苗重、芽长和根长显著增加（P〈0.05）,硬实种子数、霉变种子数显著减少（P〈0.05）。[结论]空间诱变对苜蓿二代种子有显著的正向诱变效应。     

卫星搭载对紫花苜蓿当代植株生物量的影响

[目的]了解卫星搭载对紫花苜蓿当代植株生物量的影响。[方法]3个品系的苜蓿种子搭载"实践八号"育种卫星进行飞行。返地后,对其植株茎粗、初级分枝数及单株当年生物量等指标进行测定。[结果]卫星搭载后,紫花苜蓿当代植株初级分枝数和单株生物量均显著增加,茎粗无显著变化。以高于(对照平均值+3倍标准差)为标准进行筛选,获得茎粗增加变异株2株,初级分枝增加变异株5株,单株生物量增加变异株12株。[结论]获得的变异株可用于苜蓿品种改良和新品种选育,但其有利变异能否稳定遗传有待于进一步研究。     

卫星搭载对高丹草农艺性状的影响研究

[目的]探索卫星搭载对"先锋"高丹草农艺性状的影响。[方法]将搭载后的"先锋"和未搭载的作比较试验,并对其农艺性状进行比较评价。[结果]与未搭载处理相比,搭载后物候期变化不明显,但在生长速度、株高、节径、分蘖数、叶面积、叶片数、茎叶比、产量等农艺性状上都发生了变化,特别是分蘖数和叶片数发生了显著变异,表现为"多蘖型"和"丰叶型"。通过茎段扦插和宿根繁殖可以保持突变性状,但无法将其用于新品种选育。[结论]卫星搭载后,"先锋"高丹草的株高和产量发生了变化,但有益突变性状的有性稳定遗传是下一步研究的重点。     

航空搭载对薰衣草种子萌发的影响

[目的]研究经太空诱变后薰衣草种子发芽及出苗的变异程度。[方法]以经太空诱变的薰衣草种子为试材,与未经太空诱变的种子进行发芽及出苗比较试验;同时研究了不同赤霉素浓度及不同浸种时间对太空搭载的薰衣草种子和陆地薰衣草种子发芽和出苗的影响。[结果]太空搭载的薰衣草种子较陆地薰衣草种子的发芽势、发芽率、发芽指数和出苗率均明显下降。在清水浸泡处理下,太空种子的发芽率为25.00%,发芽势为21.50%,发芽指数为1.904,分别比陆地种子降低了70.59%、74.71%和93.58%。赤霉素处理在一定程度上提高了太空种子的发芽指标,但与陆地种子相比,发芽率、发芽势和发芽指数仍较低,差异显著。不同浓度赤霉素浸泡时间对薰衣草种子发芽影响差异不显著。当赤霉素浓度为300 mg/L时,最有利于太空种子成苗。[结论]该研究为太空薰衣草育种奠定基础。     

空间条件对草地早熟禾生长的影响

[目的]探索空间条件对草地早熟禾种子萌发与幼苗生长的影响。[方法]将草地早熟禾（Poa pratensis L.）巴润（baron）干种子进行了蒸馏水和硼酸处理后利用返回式卫星搭载,以未搭载干种子作为对照。种子搭载返回后进行发芽试验和田间小区种植试验,观察不同处理种子发芽及幼苗的生长速度、株高、分蘖数等生长情况。[结果]空间条件作用促进了草地早熟禾种子的萌发,特别是对经硼酸预处理的种子的发芽具有明显的影响 与地面对照相比,空间条件对草地早熟禾的植株高度、生长速度、分蘖数都产生了一定影响,同时发现生长矮化或分蘖数更多的植株。[结论]空间条件可对草地早熟禾种子的萌发及幼苗生长产生影响。     

夏枯草种子萌发及其幼苗生长对干旱胁迫的响应

[目的]探讨干旱胁迫对夏枯草种子及其幼苗生长的影响。[方法]采用不同浓度的聚乙二醇(PEG-6000)对夏枯草种子进行处理,测定种子发芽率、发芽指数、发芽势以及幼苗的主根长、株高、鲜重、干重等指标。[结果]随干旱强度的增加,不同浓度的PEG干旱胁迫对夏枯草种子萌发及幼苗生长产生不同程度的影响。[结论]低浓度(2.5%~5.0%)PEG胁迫作用小,高浓度(10.0%~15.0%)PEG胁迫作用大;10.0%浓度PEG促使地下根长生长;对于地上部分,低浓度抑制不明显,高浓度各指标均产生显著抑制。