减压处理对梨枣果实采后生理及贮藏效果的影响

以梨枣为试材,研究了减压处理对梨枣果实呼吸强度、CAT活性、MDA含量、果肉组织相对电导率、VC含量和果肉硬度的影响。结果表明,减压处理在一定程度上降低了梨枣的呼吸强度,有效地保持了CAT活性,减少了MDA的积累,显著降低了果肉组织相对电导率,有效地保持了果肉硬度和VC含量,从而延缓了果实的成熟衰老。     

PP333对马铃薯试管苗抗氧化酶及蛋白质含量的影响

为探明PP333对马铃薯试管苗壮苗及离体保存延缓衰老的作用机理。本试验以马铃薯试管苗为材料,在MS培养基中添加不同浓度PP333,测定其生长过程中CAT、POD、SOD等抗氧化酶活性及MDA和可溶性蛋白含量的动态生理指标。结果显示：0.01、0.05及0.25 mg/L PP333处理,诱导了CAT、POD、SOD等抗氧化酶活性的上升,保持了膜脂过氧化产物MDA相对较低的含量水平,并延缓了可溶性蛋白的下降。而1.25 mg/L PP333处理,虽有较高的CAT、POD活性,但SOD活性低,可溶性蛋白明显下降。由此可知,低浓度（0.01~0.25 mg/L）PP333可保持较高的抗氧化酶和蛋白质水平以及较低含量的MDA,从而培育壮苗和延缓试管苗的衰老。较高浓度（1.25 mg/L）PP333则使蛋白质含量和SOD活性降低,表现出一定的毒害作用。     

1-MCP处理对杨梅果实贮藏期间品质及活性氧代谢的影响

为研究1-甲基环丙烯(l-MCP)对杨梅果实贮藏期间衰老的影响,本试验以"东魁"杨梅为试材,以常规冷藏为对照,研究不同1-MCP处理浓度与处理时间对杨梅果实品质和活性氧代谢的影响.结果表明:l-MCP处理可有效降低杨梅果实采后腐烂率,抑制H2O2累积,缓解VC和GSH的降解,诱导SOD、CAT和POD活性的升高,且1.0μL/L 1-MCP处理24 h的效果最佳;贮藏15 d时,1.0μL/L 1-MCP熏蒸24 h组的果实腐烂率与H2O2含量较对照组分别下降了48.25个百分点和128.58 mmol/mg Pro,SOD、CAT、POD活性较对照组分别提高了56.89、3.04、195.00 U/mg Pro,GSH和VC含量分别升高了18.67 mg/mg Pro和7.71 mg/100 g.由此可见,1-MCP处理可通过提高杨梅果实的SOD、CAT、POD等抗氧化酶活性及GSH和VC含量以有效清除活性氧自由基,从而延缓杨梅果实采后衰老,延长其保鲜时间.     

外源调节物质对棉花幼苗耐寒生理特性的效应

以棉花幼苗为试材,叶面分别喷施外源调节物质水杨酸(SA)、壳聚糖(CTS)、水杨酸+壳聚糖(SCM)、水杨酸+壳聚糖+硝酸钙(SCCa M)后,在5℃低温下进行处理,分别于0、24 h、48 h及恢复处理24 h时测定相对电导率、MDA含量、叶绿素含量,SOD、POD、CAT的活性和可溶性蛋白、可溶性糖、脯氨酸的含量。结果表明:低温胁迫前用0.7 mmol·L-1水杨酸、0.6 mmol·L-1壳聚糖及复配制剂处理棉花幼苗,其叶片的SOD、POD、CAT活性和叶绿素、可溶性蛋白、可溶性糖、脯氨酸含量与对照相比均有不同程度的提高,相对电导率和MDA含量有所降低;复配制剂处理效果优于水杨酸和壳聚糖单独施用的效果,而水杨酸、壳聚糖、硝酸钙三元复配的效果比水杨酸和壳聚糖两元复配的效果好。表明水杨酸、壳聚糖和硝酸钙在诱导棉花幼苗耐寒性中具有协同效应。     

DMTU对香石竹切花花瓣水分胁迫的抗氧化效应

以香石竹切花马斯特品种为试材,以0、5 mmol/L、10 mmol/L三种浓度的二甲基硫脲(DMTU)作为瓶插液,对不同瓶插时期的香石竹切花花瓣细胞保护酶活性进行测定,以期从细胞膜保护酶水平上明确H2O2外源抑制剂DMTU改善香石竹切花应对水分胁迫能力的机理。实验结果显示:在瓶插前期用DMTU处理的超氧化物歧化酶(SOD)活性变化平稳,过氧化物酶(POD)活性显著高于对照,瓶插后期用DMTU处理的SOD活性、过氧化氢酶(CAT)活性均显著高于对照,POD活性低于对照,说明DMTU在瓶插早期主要对POD起到了保护作用,而瓶插后期主要对SOD和CAT起到了保护作用。对不同DMTU的浓度而言,浓度为10 mmol/L清除活性氧、维持保护酶活性的作用更强,但是10 mmol/L处理的瓶插寿命短于5 mmol/L处理,5 mmol/L处理的瓶插寿命长于对照,因此DMTU的处理浓度以5 mmol/L为宜。由此可见DMTU在香石竹切花衰老时可清除活性氧,提高保护酶活性,从而缓解水分胁迫带来的膜脂过氧化,延缓花瓣衰老进程,延长其瓶插寿命。     

果实成熟衰老与保护酶系统的关系

果实成熟衰老与活性氧代谢和膜脂过氧化作用有关。自由基清除剂中SOD、POD、CAT等保护酶系统可以有效地清除活性氧、自由基,保持体内活性氧的平衡,降低膜脂过氧化作用和MDA积累量。SOD、POD、CAT等酶活性的高低可以作为判定果实耐藏性大小的指标和果实成熟衰老的标志。在贮藏过程中,果实的SOD、POD、CAT活性会发生变化,且在不同种类果实中表现出不同趋势。贮藏温度、气体指标等贮藏条件和振动胁迫、冷激、热激、涂膜等处理会影响到SOD、POD、CAT活性的大小,从而影响果实的成熟衰老进程。     

褪黑素处理对百香果采后生理及质构特性的影响

为探讨褪黑素处理对百香果采后生理及质构特性的影响,分别用褪黑素(200 μmol/L)和清水(CK)处理百香果,研究其在4℃冷藏期间果实的失重率、细胞膜通透性、丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性及质构特性的变化.结果 表明,200 μmol/L褪黑素处理组能有效减少百香果贮藏期间的水分损失,延缓百香果失重率的增加,保持果实较好的SOD和CAT活性水平,抑制POD活性和MDA的积累,降低细胞膜透性,保持百香果果实细胞膜的完整性,从而保持果实良好的采后品质,延缓果实衰老.     

NaCl胁迫对马铃薯组培苗生理生化的影响

为探究盐胁迫对马铃薯生理的影响,以耐盐品种‘陇薯5号’组培苗为试材,采取添加0 mmol/L,100 mmol/L,300 mmol/L,500 mmol/L,700 mmol/L和900 mmol/L NaCl的MS培养基模拟盐胁迫的方法,筛选盐胁迫生理测定的适宜盐浓度,并测定适宜胁迫浓度下(0 mmol/L NaCl为对照)、胁迫不同时间(0, 20 h, 24 h,48 h, 72 h和96 h)的过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和过氧化物酶(POD)等抗氧化酶的活性,膜脂过氧化物质丙二醛(MDA)含量,脯氨酸(PRO)、可溶性蛋白和可溶性糖等可溶性物质的含量。结果表明,这7项参数可以作为马铃薯耐盐性鉴定的生理指标,CAT活性与其他指标呈负相关,其他各指标彼此之间均显著或极显著正相关;与对照相比CAT活性整体呈下降趋势,POD活性和SOD活性相对含量上升;MDA含量增幅较小;在24 h时与对照相比,PRO、可溶性蛋白和可溶性糖含量增幅分别为-1%、45.3%和83.8%,而在48 h当PRO相对增幅达380%时,可溶性蛋白和可溶性糖相对增量减少。因此盐胁迫下马铃薯可能通过提高抗氧化酶活性,增加并有序调节可溶性物质来增强耐盐性。本研究为深入研究马铃薯盐胁迫生理机制,筛选和培育耐盐品种提供参考。     

追施氮肥对灌浆期沙地饲用燕麦叶片衰老特性的影响

为探究氮素对饲用燕麦叶片衰老特性的影响,在科尔沁沙地,以燕麦为材料,于苗期、分蘖期、拔节期、抽穗期按照15%,40%,25%,20%比例,对燕麦追施0(CK),70,140,210,280 kg/hm~2纯氮,检测灌浆期燕麦叶片的叶面积、叶绿素含量、可溶性蛋白含量、抗氧化酶活性及膜脂过氧化程度。结果表明:追施氮肥对延缓叶片衰老、提高功能叶作用时间和效率有明显作用。在一定范围内随着施氮量的增加,饲用燕麦的叶面积、叶绿素含量均显著提高,可溶性蛋白含量增加,而MDA含量明显降低,SOD活性显著下降,POD活性和CAT活性显著增强,延缓叶片的衰老进程。当施氮量超过210 kg/hm~2后,继续增施氮肥旗叶叶面积、叶绿素含量及可溶性蛋白含量均明显下降,且不能持续提高花后叶片POD和CAT活性,但SOD活性显著增强,MDA含量显著升高。试验亦表明,清除植物体内氧自由基并非单一的酶作用结果,取决于SOD、POD、CAT保护酶系协同作用,在科尔沁沙地追施210 kg/hm~2氮肥,饲用燕麦叶片抗衰老能力最强。     

褪黑素处理对采后梨果实品质及相关生理指标的影响

为探究褪黑素在维持采后梨果实品质方面的潜力,为采后梨贮藏保鲜技术研发提供参考,以成熟期采收的新梨7号梨果实为试材,分别用0(对照),0.02,0.20,1.00 mmol/L的褪黑素溶液浸泡2,4,8,12,24 h后取样,测定了各处理对采后梨果实内在品质、细胞壁裂解相关酶活性、抗氧化相关酶活性及果皮与果肉内源褪黑素和水杨酸含量的影响。结果表明,用0.02,0.20,1.00 mmol/L褪黑素浸泡梨果实8 h,梨果实的硬度分别为38.51,42.79,40.95 N/cm²,乙烯释放速率分别比对照下降了66%,70%,71%;用0.20 mmol/L褪黑素浸泡梨果实8 h,果实的可溶性固形物含量(SSC)为94 g/L,显著高于对照组(80.2 g/L),为对照组的1.17倍,果实的可滴定酸(TAC)为1.013 g/L,也显著高于对照组(0.90 g/L),为对照组的1.13倍;此外,外源褪黑素处理显著提高了采后梨果实超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性,显著降低了采后梨果实多聚半乳糖醛酸酶(PG)、果胶甲酯酶(PME)、...     

烟苗生长发育对不同氮源形态的响应

为探讨不同形态氮源对烟苗素质和生长发育的影响，以烤烟新品系HN2146为参试材料，采用水培试验研究硝酸铵、硝酸钙、硫酸铵和尿素4种不同形态氮源对烟苗生长发育特性的影响。结果表明，烟苗最大叶面积以硝酸钙处理最大，为100.4cm2；烟苗叶和根系蛋白质含量以硫酸铵处理最高，分别为151.452和79.367μg/g FW；硝酸还原酶活性表现为硝酸钙>硝酸铵>硫酸铵>尿素处理；烟苗对氮的吸收能力表现为硝酸铵>硫酸铵>硝酸钙>尿素处理。通过对不同处理烟苗相关农艺性状和生理特性指标的主成分分析，其综合得分表现为硝酸钙>硝酸铵>硫酸铵>尿素处理。可见以硝态氮和铵态氮作为唯一氮源对烟苗生长发育的效果较好，而以尿素作为唯一氮源的效果最差，本研究结果为不同氮源在烤烟育苗培育上的应用提供了理论依据。     

气调贮藏对冬枣采后生理及有害物质 积累的影响

探讨冬枣的采后生理特性,为选择最佳气调贮藏条件和方法提供理论依据。以鲁北冬枣为试材,研究了不同气调指标对冬枣果实中乙醛和乙醇有害物质积累的影响。结果表明,适当的低O2可以有效抑制枣果果肉硬度的下降,维持细胞膜的完整性,减缓Vc的损失,同时没有引起果肉中乙醛和乙醇的大量积累,延缓了果实的衰老。而贮藏环境中的CO2会促使枣果无氧呼吸,加速了果实中乙醛和乙醇的积累,进而加强果肉伤害,破坏细胞膜的完整性,Vc损失加剧,加快了枣果的软化衰老进程。研究表明,2%O2+0%CO2的气调指标对冬枣贮藏最有利。     

Strategies to Improve the Use Efficiency of Mineral Fertilizer Nitrogen Applied to Winter Wheat

Recovery of fertilizer nitrogen (N) applied to winter wheat crops at tillering in spring is lower than that of N applied at later growth stages because of higher losses and immobilization of N. Two strategies to reduce early N losses and N immobilization and to increase N availability for winter wheat, which should result in an improved N use efficiency (= higher N uptake and/or increased yield per unit fertilizer N), were evaluated. First, 16 winter wheat trials (eight sites in each of 1996 and 1997) were conducted to investigate the effects of reduced and increased N application rates at tillering and stem elongation, respectively, on yield and N uptake of grain. In treatment 90‐70‐60 (90 kg N ha^?1 at tillering, 70 kg N ha^?1 at stem elongation and 60 kg N ha^?1 at ear emergence), the average values for grain yield and grain N removal were up to 3.1 and 5.0 % higher than in treatment 120‐40‐60, reflecting conventional fertilizer practice. Higher grain N removal for the treatment with reduced N rates at tillering, 90‐70‐60, was attributed to lower N immobilization (and N losses), which increased fertilizer N availability. Secondly, as microorganisms prefer NH₄⁺ to NO₃^? for N immobilization, higher net N immobilization would be expected after application of the ammonium‐N form. In a pot experiment, net N immobilization was higher and dry matter yields and crop N contents at harvest were lower with ammonium (ammonium sulphate + nitrification inhibitor Dicyandiamide) than with nitrate (calcium nitrate) nutrition. Five field trials were then conducted to compare calcium nitrate (CN) and calcium ammonium nitrate (CAN) nutrition at tillering, followed by two CAN applications for both treatments. At harvest, crop N and grain yield were higher in the CN than in the CAN treatment at each N supply level. In conclusion, fertilizer N use efficiency in winter wheat can be improved if N availability to the crops is increased as a result of reduced N immobilization (and N losses) early in the growth period. N application systems could be modified towards strategies with lower N applications at tillering compensated by higher N dressing applications later. An additional advantage is expected to result from use of nitrate‐N fertilizers at tillering.     

Effect of Timing and Nitrogen Fertilizer Application on Winter Oilseed Rape (Brassica napus L.). II. Nitrogen Uptake Dynamics and Fertilizer Efficiency

Field experiments were carried out on grey‐brown podzolic soil in the four consecutive growing seasons (1998–2001) at Krzeslice Farm, central‐western Poland. The effect of seven N fertilization treatments (in kg N ha^?1): 80_NF + 80_CAN; 80_NF + 50_CAN + 30_CN; 80_CAN + 80_CAN; 80_CAN + 80_CAN + 30_CN; 80_AN + 80_AN; 80_AN + 50_AN + 30_CN, where, NF – nitrofos NPK, CAN – calcium‐ammonium nitrate, AN – ammonium nitrate, CN – calcium nitrate and control (without N) on N uptake dynamics and N efficiency was studied. Mineral fertilizers were applied at the start of spring regrowth, beginning of stem elongation and at the flower‐bud‐visibility stage. The study revealed two distinct strategies of oilseed rape plants’ adaptation to timing and N fertilizer application sequences. Both strategies based on nitrogen uptake rate (NUR), were analysed at different plant growth stages. Ammonium nitrate (AN) applied in the two‐split system gave the highest NUR (387 mg m^?2 day^?1) during stem elongation (for comparison, a value of 166 mg m^?2 day^?1 was obtained in the control). In the case of calcium‐ammonium nitrate (CAN), a moderate level of NUR was obtained (304 mg m^?2 day^?1) but N uptake lasted 12 days longer compared with the AN treatment. Hence, N accumulation in leaves at the end of flowering explained about 81 % of yield variability. The second adaptation strategy was attributed to the three‐split N treatment. Plants fertilized with AN and CAN fertilizers showed an inconsistent pattern of NUR with time. Nitrogen accumulation in stems at the beginning of maturity, explained 69 % of yield variability. Nitrogen‐use efficiency did not show any response to N treatments.     

双氰胺对马铃薯农田土壤全氮及N_(min)含量的影响

通过田间试验,研究双氰胺(DCD)对块茎类蔬菜马铃薯各个生长时期农田土壤全氮含量、Nmin的影响。试验种肥采用4个不同处理:铵态氮肥+过磷酸钙+双氰胺、铵态氮肥+过磷酸钙、硝态氮肥+过磷酸钙、过磷酸钙。采用比色法测定不同生育期马铃薯根系土壤全氮含量。结果表明:加入双氰胺后,土壤中全氮含量均显著提高(P0.05),说明双氰胺起到了抑制硝化的作用;与铵态氮肥相比,施用相同数量的硝态氮肥,土壤中Nmin的含量较大,这意味着马铃薯可能吸收较多的铵态氮,或在此试验田条件下,使用铵态氮肥的损失较大;由于硝态氮肥增产效果最好,而且铵态氮肥中添加双氰胺未引起马铃薯产量显著提高,所以施用硝态氮肥,土壤中Nmin的含量较高可能是铵态氮肥损失较大的原因所致,而非马铃薯吸收较多的铵态氮的缘故。     

Effect of Timing and Nitrogen Fertilizer Application on Winter Oilseed Rape (Brassica napus L.). I. Growth Dynamics and Seed Yield

The field experiments conducted on the grey‐brown podzolic soil in the four growing seasons (1998–2001) at Krzeslice Farm, central‐western Poland comprised seven fertilization variants: 80_NF + 80_CAN; 80_CAN + 80_CAN; 80_AN + 80_AN; 80_NF + 50_CAN + 30_CN; 80_CAN + 50_CAN +30_CN; 80_AN + 50_AN + 30_CN (where NF – nitrofos NPK; CAN – calcium‐ammonium nitrate; AN – ammonium nitrate; CN – calcium nitrate) and control (without N) applied in split rates at the beginning of spring regrowth (80 kg N ha^?1), stem elongation (80 or 50) and flower buds visible stages (30). The yielding effect of tested fertilization variants was significant in comparison with the control (2.24 t ha^?1). The highest mean seed yield (3.64 t ha^?1) was collected from 80_AN + 80_AN and 80_CAN + 80_CAN variants. Mean values of 4 years indicate that the second N rate division (80 + 50 + 30) decreased yield, although not significantly in comparison with these two N treatments. Plants grown on these treatments have developed different patterns of growth to yield the seeds. These patterns were characterized by very high crop growth rate during flowering (above 21 g m^?2 day^?1) and negative at maturation (down to ?2.5 g m^?2 day^?1). Plants fertilized with ammonium nitrate (80_AN + 80_AN) reached maximum growth rate earlier (65 days), which lasted longer (20 days) than plants fertilized with calcium‐ammonium nitrate (71 days lasting 17.5 days). Plants grown on the control treatment reached the highest crop growth rate within 79 days (14.8 g m^?2 day^?1), which lasted 15 days.     

双氰胺对马铃薯农田土壤铵态氮、硝态氮转化的影响

通过田间试验,研究双氰胺(DCD)对块茎类蔬菜马铃薯各个生长时期农田土壤铵态氮、硝态氮转化的影响。结果表明：加入双氰胺后,土壤中铵态氮含量均显著提高（p＜0.05）,硝态氮含量显著降低（p＜0.05）。     

外源钙对刺芹侧耳菌种及子实体生长发育的影响

刺芹侧耳菌丝体对外源的钙有较好的富集能力,可以将无机态的钙转变为更易被人体吸收的有机钙,为研制一种更高效、低廉、安全的补钙食品有重要的现实意义。研究通过添加五种不同的外源钙(氯化钙,硝酸钙,碳酸钙,乳酸钙,氨基酸螯合钙)对刺芹侧耳菌丝生长和子实体发育的影响,筛选出最适合刺芹侧耳菌株“L2702”的外源钙为乳酸钙,并确定刺芹侧耳菌丝体对其耐受钙的浓度范围为0~0.6 mg/mL。通过在不同浓度的乳酸钙的培养料培养下,刺芹侧耳子实体中可溶性总糖和可溶性蛋白随着浓度的升高呈现正态分布,确定浓度为0.6 mg/mL处理组为最适合的浓度,显著高于无外源钙组(p<0.05);不同浓度乳酸钙对刺芹侧耳子实体脂肪和游离氨基酸的影响不明显,无显著差异;最适浓度的乳酸钙提高了刺芹侧耳子实体的产量,缩短了其生长周期;在栽培料中添加乳酸钙,钙含量随着乳酸钙浓度的增加而增加,但子实体中钙含量呈现正态分布,最适合的浓度为0.6 mg/mL。结果表明,刺芹侧耳对外源钙具有很强的生物富集能力,可能是菌丝体的特定成分如总糖、蛋白等协同抗氧化酶系增强了菌体对外源钙的耐受性及富集特性。     

Improving storability of persimmon cv. Rojo Brillante by combined use of preharvest and postharvest treatments

The combined use of preharvest treatments, gibberellic acid (GA₃) or calcium nitrate, with 1-methylcyclopropene (1-MCP) treatment applied postharvest, was evaluated to improve the storability of ‘Rojo Brillante’ persimmon fruit, at both 1 and 15 °C. Properties linked to commercial quality, such as flesh firmness, external colour, total soluble solids and level of astringency, were evaluated at harvest, periodically during storage, as well as after subsequent shelf-life periods. At both storage temperatures, control fruit and calcium nitrate-treated fruit showed commercial quality for 20 d; the sole application of GA₃ delayed loss of firmness for 30 d while the treatment with 1-MCP by itself allowed storage of the fruit for 40 d. The combined use of calcium nitrate plus 1-MCP did not improve maintenance of quality any more than when 1-MCP was applied alone. The combination of GA₃ and 1-MCP delayed the symptoms of chilling injury, extending the storability at 1 °C for up to nearly 3 months. During storage at 15 °C, the combination of both treatments resulted in high-firmness values for 30 d, but did not prolong the storage period any longer than the 40 d reached by the sole application of 1-MCP. Irrespective of treatment, a loss of efficacy of the deastringency treatment was observed after 30 d of storage at 15 °C.