牧草太空育种的研究现状与展望

【目的】牧草太空育种是近三十年来新兴的一种育种技术,具有变异多、变幅大、稳定快等特点,可缩短牧草育种周期。本文综述了太空育种的研究现状,分析总结了太空育种的原理、方法及可能存在的问题,以期为今后牧草太空育种提供更多参考和启发。【方法】通过Web of Science、Google Scholar、中国知网、百度学术等网站查阅了大量太空育种尤其是牧草太空育种的相关文献,并对文献资料进行收集、分析和整理。【结果】太空环境诱变是当今牧草育种重要发展方向之一,通过总结太空诱变技术在牧草育种中的应用,分析了牧草太空育种中面临的问题和挑战,展望了采用太空环境诱变创制牧草新品种的前景。【结论】太空环境诱变能诱发牧草基因组中的突变,增加其遗传多样性,从而创造出具有新特性的植物品种,对牧草类作物进行种质资源的创制具有重大意义,同时也为快速培育优良牧草新品种及特异种质资源开辟了一条新途径。太空育种技术为牧草育种开辟了新的可能性,有望成为未来太空农业的重要组成部分。

围栏封育和自由放牧对伊犁绢蒿生长规律和内源激素的影响

【目的)研究围栏封育和自由放牧对伊犁绢蒿(Seriphidium transiliense)生长规律和内源激素水平的影响,分析蒿属荒漠草地围栏封育效果,为退化的蒿属荒漠草地生态系统中植被恢复研究提供理论参考依据。【方法】以围栏封育和自由放牧条件下的伊犁绢蒿为研究对象,利用植物学、植物生理学和草地管理学中有关植物形态、植物内源激素和“四度一量”方法,计数统计伊犁绢蒿高度PH、盖度PC、密度PD、生物量B、一级分枝PBN和二级分枝SBN,采取烘干法测定单株叶片干重、单株茎干重和单株根系干重,采取靶向测定内源激素(细胞分裂素IAA、脱落酸ABA、生长素CTK、赤霉素GAs、乙烯ETH)含量,每处理设置3条样线,每样线测定40个样方,对比分析各项指标,归纳总结伊犁绢蒿在两个处理下的生长规律和内源激素变化。【结果】围栏封育条件下的伊犁绢蒿株高是自由放牧株高的2.57倍,生物量是自由放牧的29.73倍,一级分枝是自由放牧的7倍,单株叶片干重、茎干重和根系干重分别是自由放牧的7.87倍、5.21倍和5.64倍;围栏封育和自由放牧对伊犁绢蒿叶片CTK和ABA含量影响较大,且差异显著(P<0.05);对伊犁绢蒿茎内源激素含量除了赤霉素(GAs)在2个处理间差异不显著以外,其他指标在两个处理间差异均极显著(P<0.01)。围栏封育对伊犁绢蒿根系内源激素影响较小,仅ETH含量在二者之间差异显著(P<0.05)。【结论】围栏封育4年,不仅使伊犁绢蒿形态特征、生长趋势与自由放牧的小型化和矮化形成鲜明对比,尤其叶片和茎的IAA和CTK含量与植株高度和一级分枝数之间关系更密切。

播种方式对博洛塔绢蒿种子出苗及幼苗生长的影响

【目的】在平原荒漠草地围栏封育的基础上,探究不同播种方式对博洛塔绢蒿种子出苗及幼苗生长的影响。【方法】试验采用包衣种撒播、包衣种条播、包衣种穴播、裸种撒播、裸种条播和裸种穴播6个处理对比分析博洛塔绢蒿出苗和植株次年返青情况,以及利用盆栽控水分析幼苗根系生长规律。【结果】不同播种方式对比分析显示,裸种穴播的出苗和植株次年返青情况均优于其他处理。博洛塔绢蒿实生苗最长根系值与盆栽试验相似,盆栽试验的须根系不如野外试验的须根系发达。【结论】选择裸种穴播,且播种当年5月底,植株根系生长超过15 cm,植株生命才能得以延续。

干旱胁迫下心叶驼绒藜生理响应特性

以心叶驼绒藜(Krascheninnikovia ewersmannia)为研究材料,用0(CK)、5%、15%、25%、30%、35%聚乙二醇(PEG-6000)模拟干旱胁迫,从渗透性调节物质、保护性物质、脂肪酸组分等方面研究其对胁迫的生理响应。结果显示,在5%、15%低浓度PEG处理下,驼绒藜幼苗通过增加渗透调节物质脯氨酸含量、启动抗氧化酶系统、保持膜脂中的饱和脂肪酸和不饱和脂肪酸动态平衡来减弱膜脂过氧化对细胞膜系统的损害;在25%PEG处理下,丙二醛含量急剧增加,叶片膜脂过氧化程度加重,植物通过大幅提高脯氨酸含量、增强抗氧化酶活性、增大膜脂中不饱和脂肪酸含量减少干旱胁迫带来的膜脂损伤;在30%、35%高浓度PEG处理下,脯氨酸含量下降、抗氧化酶系统活性降低、饱和脂肪酸含量增加,膜脂受损害严重。由此得出,驼绒藜幼苗在PEG处理液为25%时,渗透调节物质、保护性物质、不饱和脂肪酸等物质协同作用形成高效的防御系统以增强对干旱胁迫的抗性。

佳能紫花苜蓿和扁穗冰草混播比例对播种当年牧草生产性能的影响

【目的】新疆地处我国西北部,依据新疆的气候特征与现代畜牧业的急速发展所需的牧草种植需求。【方法】在探明种植比例对牧草生产性能影响的基础上,归纳出相对双优的混播模式,以紫花苜蓿、扁穗冰草两种牧草按豆禾比例(3∶7、4∶6、5∶5、6∶4、7∶3)进行同行种植人工草地与单播对比,分析其播种当年生长指标、茎叶比、生物量贡献率的变化。【结果】紫花苜蓿和扁穗冰草分别在4∶6和7∶3时株高趋于最高;紫花苜蓿在3∶7时叶长叶宽显示最高,扁穗冰草在6∶4比例下叶长最高和在单播下的叶宽最高;在叶茎比的对比下3∶7比例中紫花苜蓿品质较高和单播扁穗冰草品质较高。【结论】混播有利于提升牧草株高、叶长叶宽、叶茎比、生物量贡献率。

Effects of Enclosure on Plant and Soil Restoration in the Junggar Desert

Enclosure is commonly used in the restoration of degraded grasslands.However,the effects of enclosure on grassland plant and soil restoration remain controversial,particularly in deserts.To assess the effects of enclosure on desert plants and soil properties,using high throughput sequencing,the differences between plants and soil were systematically analyzed before and after enclosure construction.The soil organic carbon,total nitrogen and total phosphorus contents of the three desert flora increased and decreased,but the difference was not significant;enclosure increased plant height,coverage,aboveground biomass,and species richness by 58.99%,59.35%,33.29%,and 51.21%,respectively,in a Seriphidium transiliense formation;by 15.49%,33.52%,20.85%,and 5.13%,respectively,in a Haloxylon persicum formation;and by 83.80%,31.51%,76.66%and 33.33%,respectively,in an Anabasis salsa formation.For soil bacteria,enclosure significantly increased the average number of operational taxonomic units and Shannon-Wiener index by 12.74% and 2.92%,respectively,under S.transiliense formation and by 17.08% and 3.17%,respectively,under H.persicum formation.However,enclosure had no significant effect on the average number of operational taxonomic units or Shannon-Wiener index under A.salsa formation.Enclosure significantly increased desert plants,soil bacterial diversity,and desert plant community productivity;however,the increase in soil nutrient content was not significant.These results demonstrate that enclosure is effective for restoring desert ecosystems but may have little effect on the soil nutrient content.

Study on Seed Bank Composition and Seedling Emergence Regularity in Placer Iron Ore Soil

The mining of placer iron ore greatly influences the surrounding desert grassland.In Agdala Town,Qinghe County,Xinjiang,the soil seed bank is severely damaged,and the utilization and productivity of desert grasslands are almost zero,which seriously affects the safety of the ecological environment and the development of local animal husbandry.It is very important to supplement soil seed banks to enhance the species composition of desert grasslands after ecological restoration.In this study,the effects of the seed bank,species composition,and seed burial depth on the seedling emergence rate at placer iron ore site before and after artificial seed bank replenishment were compared using the germination tray method.The original soil seed bank in the study area contained only four species,which were all annual plants.The dominant species were Salsola ruthenica and Corispermum orientale,and the soil seed bank density was very small.The emergence regularity of the soil seed bank was closely related to water content,and the emergence of annual vegetation was explosive.Seed burial depth affected the emergence rate of perennial grass,and we determined that a burial depth of 0–5 cm was the most effective for emergence.This indicates that seedling emergence of artificially supplemented soil seed bank can be completed within 7 days if the sowing depth is appropriate;sowing depths greater than 5 cm affect seed germination.These findings provide a basis for selecting species to populate large areas.