干旱胁迫下聚丙烯酰胺浸种对谷子种子萌发及幼苗期抗旱性的影响

为探讨聚丙烯酰胺(PAM)浸种对谷子抗旱萌发的影响,本研究通过聚丙烯酰胺(PAM)浸种晋谷21种子,用18%的PEG 6000溶液模拟土壤干旱,研究了不同浓度的PAM溶液(0.1%、0.5%、1.0%、5.0%、7.0%、10.0%)浸种对干旱胁迫下谷子种子萌发及幼苗生长中各项生理指标的影响。结果表明:干旱胁迫下的谷子发芽能力显著低于正常水分条件,幼苗中SOD、POD、CAT的活性、Pro、O2-以及MDA的含量均增加,但可溶性蛋白的含量降低;1.0%~7.0%的PAM溶液浸种可明显促进干旱胁迫下谷子种子的萌发和幼苗生长,有效提高幼苗活性氧清除系统中抗氧化酶的活性,增加渗透调节物质的含量,减少O2-和MDA的积累。综合分析,筛选出用于谷子浸种的最佳PAM浓度为5.0%。结果表明,适当浓度的聚丙烯酰胺浸种可缓解干旱胁迫对谷子萌发和幼苗生长造成的伤害,增强谷子的抗旱性,这为PAM在生产实践中的应用提供了理论依据。     

渗透胁迫下Ca2+/CaM信使系统对小麦幼苗生理特性的调控效应

为探讨Ca2+/CaM信使系统对渗透胁迫下小麦幼苗生理特性的调控效应,以豫麦49-198为材料,研究了Ca2+通道阻断剂异博啶(VP)和CaM拮抗剂盐酸氯丙嗪(CPZ)对PEG胁迫下小麦幼苗相对含水量、丙二醛(MDA)、超氧阴离子(O2·-)、双氧水(H2O2)、可溶性糖、可溶性蛋白质、脯氨酸和谷胱甘肽(GSH)含量以及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性的影响.结果表明,随着渗透胁迫时间延长,VP和CPZ处理提高了小麦幼苗MDA、O2·-和H2O2含量,降低了相对含水量、可溶性糖、脯氨酸、可溶性蛋白质和GSH含量,抑制了SOD、POD和CAT活性,而且VP和CPZ复合处理对小麦幼苗的伤害程度更大.试验表明,Ca2+/CaM信使系统可能通过提高渗透调节物质和抗氧化剂含量、增强抗氧化酶活性、降低膜质过氧化水平调节小麦幼苗对渗透胁迫的适应性.     

小麦/玉米萌发和苗期生长对干旱与低温的响应

春旱和低温是影响东北作物生长的气候问题之一。以禾本科作物玉米和小麦为对象,模拟低温和干旱的单一及复合胁迫对其萌发和早期幼苗生长的影响。结果表明,低温和干旱,单一和复合胁迫均显著影响着小麦和玉米种子的萌发及早期幼苗生长。小麦幼苗在15℃~25℃和0~20%的PEG水平下,保持较高的萌发率(63.3%~87.3%),而在10℃和30%PEG浓度下显著下降,10℃和不同PEG浓度下以及30%PEG和不同温度处理下的萌发率区间分别为0~64.7%和0~18%。玉米种子在15℃~25℃和0~20%的PEG水平下,萌发率变化区间为2.22%~100%,在10℃和不同PEG浓度下以及30%的PEG处理在不同温度下的玉米种子萌发率均为0。小麦早期幼苗的长度和生物量变化趋势相似,随着干旱强度增加和温度的降低,先增加后降低,在10%的PEG水平和20℃的气温条件下,其幼苗长度和生物量值最高。玉米幼苗的长度和干重与其萌发率变化趋势一致,显著线性下降,最高值出现在0%的PEG水平和25℃的气温条件下。小麦幼苗的根冠比高于玉米。推测在较强的低温和干旱胁迫下,小麦比玉米具有更高的萌发和生长适应性。生物量向根部分布以及高根冠比值是小麦对干旱低温的适应性策略。     

不同盐分与水分胁迫对灰绿藜种子萌发效应研究

不同盐分与水分胁迫对灰绿藜种子萌发试验研究结果表明,>0 0 5mol/ L(PEG 6 0 0 0溶液渗透势为- 0 .2MPa)浓度盐溶液对灰绿藜种子萌发有明显抑制效应,而较低浓度盐溶液(较低渗透势PEG 6 0 0 0溶液)对种子萌发有促进作用。不同盐溶液对种子萌发抑制程度依次为MgCl2 >Na2 SO4>Na2 CO3 >NaCl>复合盐溶液>MgSO4。PEG 6 0 0 0溶液渗透势≤- 0 .5MPa时对种子萌发抑制作用小于等渗NaCl溶液。未萌发种子复水试验结果表明一定程度盐分与水分胁迫不影响种子萌发潜力,其萌发恢复率随原处理溶液抑制程度的增加而增加;种子萌发潜力未受影响时其忍受的最大渗透胁迫随处理溶液不同而异     

模拟干旱和盐碱胁迫对碱蓬、盐地碱蓬种子萌发的影响

为研究干旱和盐碱胁迫对碱蓬(Suaeda glauca)、盐地碱蓬(Suaeda salsa)种子萌发的影响,比较碱蓬和盐地碱蓬逆境生理特性的异同,本研究利用PEG6000、NaCl和Na_2CO_3分别模拟干旱、盐和碱胁迫,配制相同渗透势的PEG6000、NaCl、Na_2CO_3处理液,以蒸馏水处理为对照,对碱蓬、盐地碱蓬种子的萌发与胚的生长进行比较研究。结果表明:1)低渗处理(-0.46 MPa)对碱蓬、盐地碱蓬种子的萌发无显著影响;高渗处理(-1.38MPa、-1.84 MPa)抑制碱蓬、盐地碱蓬种子的萌发。2)当溶液渗透势相等时,NaCl处理下碱蓬种子的萌发率显著大于PEG、Na_2CO_3处理;而等渗PEG、NaCl、Na_2CO_3处理对盐地碱蓬种子萌发率的影响无显著差异。3)PEG、NaCl、Na_2CO_3处理组碱蓬、盐地碱蓬种子的最终萌发率与对照无显著差异。4)在幼苗形成阶段,PEG、Na_2CO_3处理对碱蓬、盐地碱蓬胚的抑制作用显著大于等渗NaCl处理。5)碱蓬、盐地碱蓬胚的生长对NaCl、Na_2CO_3胁迫的响应存在差异。-0.92 MPa NaCl处理抑制碱蓬胚的生长,却对盐地碱蓬产生促进作用;-0.46 MPa Na_2CO_3处理对碱蓬胚的抑制作用小于盐地碱蓬。综合分析表明:碱蓬、盐地碱蓬均具有很强的抗盐性。在种子萌发阶段,碱蓬种子的抗旱、抗碱能力低于盐地碱蓬;在幼苗形成阶段,碱蓬胚的抗盐性小于盐地碱蓬,但对轻度碱胁迫的抗性高于盐地碱蓬。     

硅对干旱胁迫下小麦幼苗生长及光合参数的影响

采用溶液培养试验,以两个抗旱性不同的小麦品种:低抗的扬麦9号(Yangmai.9)和高抗的豫麦18(Yumai.18)为材料,用PEG6000(聚乙二醇6000,渗透势约为-0.589MPa)模拟干旱胁迫条件,研究了硅对干旱胁迫下小麦幼苗生长、光合作用及可溶性糖含量的影响。结果表明,干旱胁迫条件下,小麦幼苗的生长和光合作用显著受到抑制,加硅处理能有效地提高干旱胁迫条件下小麦幼苗的生长状况及光合作用,且1.0.mmol/L.Si处理的效果优于0.1mmol/L.Si处理。与不加硅处理相比,干旱胁迫条件下加硅处理后,小麦幼苗的鲜干重、叶片可溶性蛋白含量、净光合速率(Pn)、蒸腾速率(Tr)、水分利用率(WUE)和气孔限制值(Ls)均显著升高,叶绿素含量也有一定程度的升高;而气孔导度(Gs)和细胞间隙CO2浓度(Ci)显著下降,可溶性糖积累量也降低。因此,硅可显著提高小麦对干旱胁迫的抗性。     

黑果枸杞种子萌发对PEG模拟干旱胁迫的响应

[目的]研究干旱胁迫对黑果枸杞种子萌发及幼苗生长的影响,为黑果枸杞人工栽培提供理论依据。[方法]通过聚乙二醇(polyethylene glycol,PEG)模拟干旱胁迫,测定不同干旱胁迫强度下黑果枸杞种子的萌发进程、发芽率、发芽势、发芽指数、活力指数、幼苗的生长、幼苗渗透调节物质、叶绿素含量等指标,研究干旱胁迫对黑果枸杞种子萌发及幼苗生长的影响。[结果]干旱胁迫不利于黑果枸杞种子的萌发,重度干旱胁迫推迟其萌发的高峰期;干旱胁迫下黑果枸杞种子的发芽率、发芽势均呈下降趋势,-0.6 MPa处理下,黑果枸杞种子发芽率、发芽势相对对照分别降低72.06%和74.07%;干旱胁迫对黑果枸杞种子发芽指数和活力指数有抑制作用,其抑制程度随干旱胁迫强度的增加而增加;适度干旱胁迫有利于黑果枸杞幼苗胚根和胚芽的生长,而中度、重度干旱胁迫不利于幼苗胚芽的生长;干旱胁迫下黑果枸杞幼苗根、芽脯氨酸含量和可溶性糖含量均随着胁迫程度的增加逐渐增加,而幼苗叶绿素含量(Chl a+b)随干旱胁迫强度的增加逐渐降低。[结论]干旱胁迫对黑果枸杞种子萌发及幼苗生长有重要影响,适度的干旱胁迫有利于黑果枸杞幼苗的生长。     

种子引发对NaCl胁迫下小麦幼苗生理特性的影响

以耐盐性强的晋农207和耐盐性弱的运麦218两个冬小麦品种种子为试材,用20%的PEG及100mmol/L的KNO3水溶液对种子进行引发处理.研究模拟NaCl胁迫环境下引发处理对小麦种子发芽、幼苗耐盐性及幼苗生理特性的影响.结果表明:两种引发处理不同程度地提高了2个品种小麦的发芽势、发芽率、发芽指数和活力指数;使2个小...     

纳米级Fe3O4分散液浸种对NaCl胁迫下番茄种子萌发及幼苗保护酶系统的影响

为揭示纳米级Fe3O4（Fe3O4NPs）调控作物耐盐的效应和机理,采用共沉淀法成功合成10 nm粒径的Fe3O4NPs,并通过了表征分析和鉴定;进一步研究其0、1、10、50、100、200、300、400 mg?L–1 分散液浸种处理对NaCl胁迫下番茄种子萌发、幼苗生长及其抗氧化的影响。结果表明：盐胁迫下1 mg?L–1 Fe3O4NPs浸种明显降低番茄种子发芽、幼苗胚根和下胚轴生长,随着浸种浓度上升,其发芽逐步得到改善;100 mmol?L–1 NaCl胁迫下,200 mg?L–1 Fe3O4NPs浸种的种子发芽势和下胚轴长达到峰值,显著高于仅盐处理的对照。100 mmol?L–1 NaCl胁迫明显降低番茄种子成苗率、幼苗鲜物质量和含水量,1 mg?L–1 Fe3O4NPs浸种,导致其进一步降低,随着Fe3O4NPs浸种浓度上升,其数值逐渐上升,200 mg?L–1 Fe3O4NPs浸种的幼苗鲜物质量和含水量达到峰值,显著高于仅盐处理的对照。盐胁迫下,1 mg?L–1 Fe3O4NPs浸种的幼苗超氧化物歧化酶（SOD）和过氧化物酶（POD）活性显著上升,而过氧化氢酶（CAT）活性下降,随着Fe3O4NPs浸种浓度上升,SOD和POD酶活逐渐下降再逐渐回升,CAT酶活逐渐上升再回落,100~200 mg ?L–1 Fe3O4NPs浸种的幼苗SOD和POD酶活、丙二醛（MDA）、脯氨酸（Pro）含量、超氧阴离子自由基（O2?－）和过氧化氢（H2O2）含量均最低,而其CAT酶活最高。相关性分析表明,幼苗鲜物质量、成苗率与SOD和POD活性以及MDA和活性氧含量均呈极显著负相关。综上所述,在盐胁迫下Fe3O4NPs浸种处理的番茄种子萌发和成苗依赖于Fe3O4NPs不同浓度的调控特征,即1 mg?L–1 Fe3O4NPs浸种处理展示了进一步抑制的典型特征,其氧化胁迫加剧;而200 mg?L–1 Fe3O4NPs浸种处理表现为促进萌发、成苗和壮苗的显著作用,与其抗氧化得到明显改善直接相关。     

表油菜素内酯对汞胁迫下小麦幼苗抗氧化系统的影响

为探讨表油菜素内酯(EBR)对小麦幼苗汞胁迫的调控作用,采用营养液水培法,研究汞胁迫下叶面喷施24-表油菜素内酯对小麦幼苗生长、叶片MDA及H2O2含量、质膜透性、抗氧化酶活性、抗氧化物质含量的影响。结果表明,50 mg·L-1汞处理小麦幼苗后,小麦幼苗的株高和干重显著降低,叶片的MDA、H2O2含量和质膜透性增加,SOD、POD和CAT活性下降,As A、GSH含量降低。与单独汞胁迫相比,叶面喷施一定浓度EBR促进了小麦幼苗的生长,降低了小麦幼苗叶片的MDA和H2O2含量,减小了质膜透性,提高了SOD、POD和CAT活性,增加了抗氧化物质As A、GSH含量,提高了As A/DHA、GSH/GSSG的比值,以EBR浓度0.01 mg·L-1为宜。综上,外源EBR可缓解汞胁迫对小麦幼苗的伤害,其机制可能与EBR能提高抗氧化酶活性及抗氧化物质含量、降低MDA和H2O2含量有关。本研究结果为降低汞污染土壤对作物生长的毒害作用提供了依据。     

蝴蝶兰的种子培养

在MS，KC，花宝三种基本培养基中，MS最适合蝴蝶兰种子的萌发，加香蕉汁150g/L可明显提高种子发芽率并促进幼苗生长；MS＋BA 3mg/L NAA 0.05mg/L也有利于蝴蝶兰种子的萌发及幼苗生长；活性炭可有效防止幼苗变褐死亡；多效唑1．5mg/L可以促进幼苗根的形成，使试管苗移载成活率达95％以上。     

籽粒黄熟度对杂交水稻种子活力的影响

为明确籽粒黄熟度对杂交水稻种子活力的影响,探究杂交水稻高活力种子适宜收获期的感官指标,于2016-2017年以深两优1813、隆两优1813、Y两优1128、创两优华占和Ⅱ优838为材料进行杂交水稻制种,通过不同收获时期形成籽粒黄熟度不同的群体,系统分析了不同籽粒黄熟度群体间种子活力、水分、千粒重及内含物的差异。结果表明,在不同品种间,籽粒黄熟度的增加速率存在明显差异。随着籽粒黄熟度的增加,种子活力先增加后趋于稳定;种子水分先降低后趋于稳定;种子千粒重逐渐增加,但差异不显著;种子的直链淀粉、总淀粉、蛋白质及可溶性糖含量均先增加后趋于稳定。当籽粒的黄熟度为75%~90%时,种子发芽率、发芽势、发芽指数和活力指数均处于高值水平,且差异不显著;种子水分和千粒重均未达到显著差异。相关性分析表明,籽粒黄熟度与种子发芽率、活力指数呈极显著正相关,相关系数分别为0.870 3^**和0.664 0^**;与种子水分呈极显著负相关(R²=-0.842 4^**),与种子千粒重相关性不显著(R²=0.197 2)。籽粒黄熟度与种子内含物均无显著相关性,但种子发芽势、发芽指数和活力指数均与种子内含物达到显著相关。综上,籽粒黄熟度为75%~90%可以作为杂交水稻高活力种子生产适宜收获期的感官指标。本研究结果为杂交水稻高活力种子生产提供了理论参考。     

中国的种子工程

简要回顾了种子产业在中国的形成和发展过程，论述了中国种子工程的特征是以农作物种子为对象，以为农业生产提供具有优秀生物学特性和优良种植特性的商品化种子为目的，通过利用现代生物学手段、工程学手段和农业经济学原理以及其它现代科技成果，按照种子科研、生产、加工、销售、管理的全过程所形成的规模化、规范化、程序化、系统化的产业整体。通过系统构成分析，提出了实施建议，并对实施前景进行了展望。     

围封草地"种子岛"效应对周围沙化草地土壤种子库的影响

在浑善达克沙地南缘，以围封7年的沙化草地以及围栏外周围不同地段作为研究对象．通过对比分析围栏外不同地段沙化草地土壤种子库特征，并以围栏内草地作对照，就围封草地的“种子岛”效应对周围沙化草地土壤种子库的影响进行了尝试性研究。结果表明：围封草地“种子岛”效应对围栏外近距离处沙化草地土壤种子库具有显著性影响．它能够以围封草地为中心，呈辐射状促进周围沙化草地土壤种子库恢复，且随着距围栏距离的增加。作用逐渐减小．并约在围栏500m外逐渐消失。     

Physical Properties of Vetch Seed

The physical properties of vetch seed were evaluated as a function of moisture content. The average length, width and thickness were 5·19, 4·33 and 3·63 mm, respectively, at 10·57% dry basis (d.b.) moisture content. In the moisture range from 10·57 to 20·63% d.b., studies on rewetted vetch seed showed that the thousand seed mass increased from 55·47 to 59·03 g, the projected area from 23·52 to 29·05 mm², the sphericity from 0·837 to 0·859, the true density from 1286·2 to 1369·9 kg m⁻³, the porosity from 33·08% to 39·68% and the terminal velocity from 9·94 to 10·33 m s⁻¹. The static coefficient of friction of vetch seed increased the linearly against surfaces of four structural materials, namely, rubber (0·350–0·387), aluminium (0·319–0·367), stainless steel (0·202–0·328) and galvanised iron (0·312–0·361) as the moisture content increased from 10·57 to 20·63% d.b. The bulk density and the shelling resistance decreased from 860·8 to 826·2 kg m⁻³ and from 148·73 to 62·68 N, respectively, with an increase in moisture content from 10·57 to 20·63% d.b.     

Seed consumption by millipedes

Seed predation is a key mortality factor for plants that reproduce by seeds. We investigated seed consumption by Cylindroiulus caeruleocinctus (Wood, 1864), an abundant representative of an unrecognised group of seed predators - the millipedes (Diplopoda: Julidae). The consumption of small seed species by millipedes was measured in the absence (41 species) and in the presence (11 species) of alternative food sources (dead leaves). We examined whether millipedes would consume seeds at all and if so whether there were any seed size constraints that determined millipede seed acceptance (i.e., the proportion of millipedes that ate seeds) and seed consumption (i.e., the mass of the seeds eaten). Our results indicated that C. caeruleocinctus readily accepted seeds with 75% of seed species accepted in a no-choice experiment and 100% of seed species in a choice experiment. Seed acceptance decreased with increasing seed mass but increased with increasing millipede mass. Seed consumption increased with the size of the offered seed species but was found to be independent of millipede mass. After the millipedes were given dead leaves to consume, the acceptance slightly decreased, and the consumption of the more preferred seed species decreased. Seeds form a small part of the millipede diet but are consumed regularly. Because of millipedes’ foraging preferences and their patchy distribution they may notably contribute to the local mortality of some seed species in their natural environment.     

Seed consumption by millipedes

Seed predation is a key mortality factor for plants that reproduce by seeds. We investigated seed consumption by Cylindroiulus caeruleocinctus (Wood, 1864), an abundant representative of an unrecognised group of seed predators – the millipedes (Diplopoda: Julidae). The consumption of small seed species by millipedes was measured in the absence (41 species) and in the presence (11 species) of alternative food sources (dead leaves). We examined whether millipedes would consume seeds at all and if so whether there were any seed size constraints that determined millipede seed acceptance (i.e., the proportion of millipedes that ate seeds) and seed consumption (i.e., the mass of the seeds eaten). Our results indicated that C. caeruleocinctus readily accepted seeds with 75% of seed species accepted in a no-choice experiment and 100% of seed species in a choice experiment. Seed acceptance decreased with increasing seed mass but increased with increasing millipede mass. Seed consumption increased with the size of the offered seed species but was found to be independent of millipede mass. After the millipedes were given dead leaves to consume, the acceptance slightly decreased, and the consumption of the more preferred seed species decreased. Seeds form a small part of the millipede diet but are consumed regularly. Because of millipedes’ foraging preferences and their patchy distribution they may notably contribute to the local mortality of some seed species in their natural environment.     

Uptake and Distribution of Arsenic in Chickpea: Effects on Seed Yield and Seed Composition

Chickpea plants were grown in arsenic (As)–contaminated soils (5 mg kg^?1 of dry soil) and investigated for As uptake, distribution, and effects on growth, yield, and quality of seeds. The roots accumulated the greatest As (7 mg kg^?1 dry weight), followed by stem (4.8 mg), leaves (4.0 mg), and seeds (0.7 mg). Arsenic inhibited the growth of the roots and shoots (as dry weight) by 65% and 60%, respectively, over controls. The shoot/root ratio declined from 4.3 in the control to 3.5 in As-treated plants. The seed yield (g) and number of pods plant^?1 decreased by 66 and 53%, respectively, over controls. A marked increase in membrane damage coupled with reduction in chlorophyll and relative leaf water content occurred in As-treated plants. The contaminated plants showed 34% and 25% decrease over control in sucrose content in their leaves and seeds, respectively. The accumulation of seed reserves such as starch, proteins, sugars, and minerals was inhibited significantly due to As-treated plants. Storage proteins such as albumins, globulins, glutelins and prolamins decreased significantly with larger effect on glutelins. The contents of minerals such as calcium (Ca), phosphorus (P), and iron (Fe) declined greatly in the seeds of As-treated plants. The accumulation of amino acids such as lysine, methionine?+?cystine, phenylalanine?+?tyrosine, proline, threonine, tryptophan, and valine was inhibited significantly in the seeds of As-applied plants compared to the control. The findings indicated that As application markedly reduced the quality of the chickpea seeds, especially in terms of proteins and minerals.     

Seed Nitrogen Mobilization in Soybean: Effects of Seed Nitrogen Content and External Nitrogen Fertility

Soybean breeding programs have developed genetic lines with relatively low seed protein, which could negatively impact early seedling growth in low fertility conditions commonly encountered in the field. In these experiments, seed protein mobilization and its regulation in situ in soybean lines with different seed protein levels was investigated. The results showed that rates of nitrogen (N) release from cotyledons were much lower with decreasing levels of N in seed. Patterns of proteolysis of the storage proteins glycinin and β -conglycinin and their subunits were not different, but breakdown rates were slower. Seed N release rates increased somewhat when external N was supplied to roots of the developing seedlings, suggesting the involvement of source/sink controls. The effect appeared to be down-stream from proteolysis, as rates of protein breakdown were not altered. The results indicate that low seed protein levels will lead to reduced seedling fitness in low fertility soil conditions unless fertilizer N is applied.     

Mechanical Properties of Wheat Seed Coats

The crumbliness of starchy endosperm and the resistance of bran are key characteristics that enhance milling behavior of wheat and are dependent on the genetic origin and moisture content of the grain. A method was developed to measure the mechanical properties of bran samples based on the measurement of tensile stress and strain. Tests conducted with this highly reproducible and sensitive method documented cultivar and moisture‐content effects (6.3, 13.8, and 18%, wb) on rheological behavior of wheat seed coats. A moisture‐dependent reduction in stress to fracture (‐15 to ‐30%) and in Young's modulus (‐45 to ‐55%) was quantified. An increase in deformation to fracture of seed coats was also correlated with bran size differences after milling. The energy required to fracture a sample (from 0.4 to 1.3 J/mm³) was considered the most valid of all presented parameters for assessing the milling behavior of wheat seed coats and the size of bran fractions.