氮离子注入变异杏抗寒性的初步研究

以三个杏树品种凯特、美特和金太阳的氮离子注入变异植株为试材,采用人工低温冷冻处理,通过对不同温度处理后枝条的半致死温度LT50,膜保护性酶SOD、POD和CAT活性,可溶性蛋白质、游离脯氨酸和丙二醛(MDA)的含量等指标的具体变化进行系统分析,探讨了它们对低温胁迫的适应机理,并进一步对比分析了变异植株和相应的栽培品种(对照)的抗寒性差异。结果表明:①凯特、美特和金太阳变异植株的LT50分别低于相应对照2.6℃、1.8℃和0.9℃;②随着处理温度的降低,变异植株的可溶性蛋白质含量逐渐高于对照(P<0.05);③随着温度的降低,MDA含量都呈现出"上升"趋势,但变异植株的MDA含量显著低于对照(P<0.05)。以上结果表明,与对照相比,变异植株低温处理可能启动了相关抗寒基因的表达,有效地减弱了变异植株细胞膜脂过氧化作用,增加了细胞膜稳定性,进而引起了抗寒性的提高。     

孕穗抽穗期低温对水稻植株、产量性状及脯氨酸含量的影响

低温是东北稻区常见的气象灾害。此试验以北方主栽粳稻品种辽星1号和辽优5218为试材,采用盆栽试验,人工控温在孕穗期、抽穗开花期进行低温胁迫,处理后立即测定叶片脯氨酸含量,成熟后调查植株和产量性状的变化,探讨生殖生长关键期低温伤害机理及叶片脯氨酸含量的变化在低温逆境中的作用。结果表明：植株性状中,株高在抽穗开花期对低温更敏感;穗抽出度则在孕穗期更敏感,穗抽出度与单株实粒数及结实率呈显著或极显著正相关,可作为抗性鉴定指标应用。产量性状中,穗粒数、单株实粒数、千粒重指标在孕穗期对低温更敏感。低温胁迫下,叶片脯氨酸含量随温度的降低、处理时间的延长而迅速上升,辽星1号最大增加2.65倍,辽优5218增加7.66倍。孕穗期低温,辽优5218叶片脯氨酸含量与穗抽出度、单株实粒数及单株结实率呈显著负相关;抽穗开花期低温,两品种叶片脯氨酸含量与株高、单株实粒数及单株结实率均呈显著负相关,辽星1号脯氨酸含量还与单株秕粒数呈极显著正相关。脯氨酸含量的变化是低温伤害程度的直观反映,把它单独作为抗性评价指标会有失真的可能。     

硅对遮荫处理草坪草可溶性糖和氨基酸含量的影响

采用基质培养法,设自然光照条件下不遮荫和遮荫2个处理,每处理设不施硅和施硅2个硅水平,测定草坪草矮脚虎和海滨雀稗可溶性糖、游离氨基酸和脯氨酸含量,研究施硅对草坪草耐荫性的影响.结果显示:遮荫处理后,矮脚虎和海滨雀稗可溶性总糖、蔗糖和还原糖含量显著下降,游离氨基酸总量显著升高.施硅后,遮荫处理与不遮荫处理的矮脚虎和海滨雀稗可溶性总糖、蔗糖及游离氨基酸总量差异减少.施硅显著提高脯氨酸含量,遮荫处理对脯氨酸影响较小.海滨雀稗可溶性总糖、蔗糖、游离氨基酸和脯氨酸含量低于矮脚虎,施硅和遮荫处理对海滨雀稗影响大于矮脚虎.结果表明:遮荫处理后草坪草非结构性碳水化合物含量下降,而施硅后硅的沉积,促进了草坪草对有限光能的利用,缓解了草坪草非结构性碳水化合物含量的下降,而提高了草坪草的耐荫性.矮脚虎耐荫性高于海滨雀稗.     

PEG胁迫下4个黑麦草品种生理生化指标响应与比较研究

利用不同浓度PEG-6000溶液模拟干旱胁迫,比较研究4个多年生黑麦草品种叶片生理生化指标响应。结果表明,不同PEG胁迫处理下,品种“欧必克”叶片相对含水量均最高且降幅最小,叶片电导率均最低,MDA含量增幅较小,叶片细胞膜系统有较强的忍耐干旱的能力;而品种“凤凰”忍耐干旱的性能相对较弱。胁迫下各品种叶片游离脯氨酸含量显著增加,随渗透胁迫加剧,品种“欧必克”脯氨酸含量急剧上升。低浓度胁迫下(5%PEG),各品种叶片SOD活性均提高,胁迫加剧时SOD活性则下降。PEG渗透胁迫导致4个多年生黑麦草品种叶片相对含水量下降、细胞膜透性增大、MDA含量增加、脯氨酸含量上升而SOD活性下降,但4个品种对应指标的变化幅度存在差异,品种“欧必克”的抗旱性最强,而“凤凰”的抗旱性最弱。     

Physiological Effects of Winter Rape (Brassica napus var. oleifera) Prehardening to Frost. II. Growth, Energy Partitioning and Water Status during Cold Acclimation

Prehardening of winter rape, i.e. its early growth in a reduced day temperature (+12°C) from emergence to the beginning of cold acclimation at chilling temperatures (the 1^st stage of cold acclimation), has a beneficial influence on frost resistance. In earlier studies it has been demonstrated that during prehardening, plants formed leaf rosettes and increased the photosynthetic efficiency at chilling temperatures. In the present study investigations were carried out on the effect of prehardening on the growth rate of the plants during the 1^st stage of cold acclimation, and the progress of selected physiological processes occurring during this stage and resulting in increased frost resistance. It has been demonstrated that a greater inflow of photoassimilates during the 1^st stage of cold acclimation results in greater increments of the dry mass of prehardened plants. These plants show also a distinct inhibition both of the elongation growth and the rate of expanding new leaves. The acquired energy is thus spent to a greater extent on the processes associated with increasing frost resistance, and not on growth. In prehardened seedlings, during the 1^st stage of cold acclimation, there have been observed in leaves a higher rate of both water content decrease and drop in the osmotic potential of the cell sap and water potential in the tissues. Also an increased accumulation of soluble sugars and free proline was noticed. However, the beginning of these processes was not observed during the prehardening period. Prehardening stimulated the effectiveness of the 1^st stage indirectly through changes leading to the increased amount of available energy and enabling the utilisation of the greater part of acquired energy in the cold acclimation process.     

冷激结合水杨酸处理对黄瓜果实冷害及能量和脯氨酸代谢的影响

为探讨冷激结合水杨酸处理减轻黄瓜果实冷害的作用及其机理,本试验分别研究了冷激(0℃冰水混合物)、水杨酸(1 mmol· L^-1)以及二者结合(含有1 mmol· L^-1水杨酸的0℃冰水混合物)3种处理方式对黄瓜果实低温贮藏期间能量和脯氨酸代谢的影响。结果表明,冷激、水杨酸以及二者结合处理均能抑制黄瓜果实冷害程度、相对电导率和丙二醛(MDA)含量的上升;还能提高 Ca²⁺-ATPase、H⁺-ATPase、琥铂酸脱氢酶(SDH)和细胞色素C氧化酶(CCO)的活性,延缓三磷酸腺苷(ATP)和二磷酸腺苷(ADP)含量的下降,抑制一磷酸腺苷(AMP)含量的上升,维持较高的能荷水平;此外,3种处理均提高了△¹-吡咯啉-5-羧酸合成酶(P5CS)和鸟氨酸-δ-氨基转移酶(OAT)活性,抑制了脯氨酸脱氢酶(PDH)活性,促进了黄瓜果实内脯氨酸的积累。在3种处理方法中,以冷激结合水杨酸处理的效果最佳。本研究为减缓黄瓜果实采后冷害提供了一定的理论依据。     

NaCl处理对海棠渗透调节的影响

研究了2年生海棠(Malus spectabilie)在0、2、4o和6oNaCl胁迫条件下有机和无机渗透调节物质的变化.结果表明,海棠在盐分处理浓度为2‰时的鲜重和干重达到最大值;随着盐分处理浓度的升高可溶性糖浓度出现急剧升高趋势,盐分处理浓度为6时比对照增加达到36.9,脯氨酸含量也升高但是趋势并不明显,可溶性蛋白含量并没有出现有规律的变化,根茎叶中的Na+含量升高,K+含量下降.综合分析认为海棠具有一定的对盐胁迫的适应能力.逐步回归分析显示可溶性糖和Na+/K+是2个较好反映海棠渗透调节能力的指标.     

Variation of Soil Microbial Biomass and Enzyme Activities at Different Growth Stages of Rice （Oryza sativa）

A pot experiment was conducted under submerged conditions with hybrid rice Zhenong 7 to study the variation in the soil microbial biomass carbon （Cmic）, soil microbial biomass nitrogen （Nmic）, soil respiration rate, soil microbial metabolic quotient, soil enzyme activities, chlorophyll content, proline content and peroxidase activity （POD） in rice leaf at different growth stages. The soil Cmic, Nmic and soil respiration rate significantly increased at the early stage and then declined during rice growth, but ascended slightly at maturity. However, soil metabolic quotient declined at all the stages. Soil urease activity increased at first and then decreased, while acid phosphatase and dehydrogenase activities descended before ascended and then descended again. Soil urease activity and acid phosphatase activity showed a peak value at the tillering stage about 30 days after rice transplanting, but the peak value of dehydrogenase activity emerged at about 50 days after rice transplanting and the three soil enzymatic activities were significantly different at the different developmental stages. As rice growing, chlorophyll content in rice leaf descended at the early stage then ascended and a peak value appeared at about the 70th after rice transplanting, after that declined drastically, while POD activity increased gradually, but proline content declined gradually. There was a slight relation between rice physiological indices and soil biochemical indices, which indicated that soil biochemical characteristics were affected significantly by rice growth in the interaction system of the rice. soil and microorganisms.     

镉、锌胁迫对番茄幼苗生长及脯氨酸和谷胱甘肽含量的影响

研究水培条件下,重金属镉、锌胁迫对番茄种子萌发、幼苗生长及相关生理指标的影响。结果表明:镉、锌溶液(2.000 mmol/L)能明显抑制种子的发芽势、发芽率和根的伸长,受抑制程度为根>发芽势>发芽率;镉(0.001 mmol/L~0.100 mmol/L)和锌(0.010 mmol/L~1.000 mmol/L)能够抑制番茄幼苗株高的增长和干物质的积累、降低叶绿素a、叶绿素b、叶绿素a b及叶绿素a/b值;番茄茎、叶含水量在高浓度处理(镉、锌营养液浓度分别为0.100 mmol/L和1.000 mmol/L)时明显降低;番茄根、叶中脯氨酸和谷胱甘肽含量均随镉、锌营养液浓度的提高而呈增加趋势,而可溶性糖含量只有当镉、锌营养液浓度分别为0.100 mmol/L和0.100 mmol/L、1.000 mmol/L时才上升。依据试验结果,作者讨论了重金属镉、锌对番茄幼苗根、叶中可溶性糖、脯氨酸和谷胱甘肽含量的作用。     

秸秆发酵液对玉米种子萌发及幼苗生长特性的影响

为了探究秸秆还田配施腐熟剂对玉米幼苗的影响,以40 g/L、50 g/L、60 g/L和70 g/L玉米秸秆-土壤浸出液自然发酵及腐熟剂发酵液为试材,用滤纸培养、盆栽法和常规方法测定种子发芽率、幼苗根长、根数、株高、幼苗鲜重、游离脯氨酸和丙二醛含量。结果表明,随发酵液浓度的增加,种子发芽率、根长、根数、根系鲜重、株高、叶片鲜重均先增加后降低的趋势;相同浓度腐熟剂发酵液的上述指标值均大于自然发酵液;其中50 g/L自然发酵和60 g/L腐熟剂发酵液种子发芽率较高;腐熟剂发酵液显著增加幼苗根长;50 g/L腐熟剂发酵液极显著增加根数;各处理对幼苗根鲜重、叶片鲜重和株高无显著影响。50 g/L自然发酵液、60 g/L腐熟剂发酵液根系和叶片游离脯氨酸及丙二醛含量与土壤浸出液无显著差异;总体看,50 g/L自然发酵及60 g/L腐熟剂发酵液对玉米幼苗生长有显著促进作用。玉米秸秆配施腐熟剂发酵可减弱其化感作用,秸秆还田配施腐熟剂时可适当增加秸秆还田量。