桃叶片中相关激素含量与树体矮化和生长的关系

为探讨相关内源激素含量与桃树树体矮化和生长的相关性,以期为桃树优良短枝型品种的选育和高效矮化密植提供理论依据,以普通型桃-春艳、短枝型桃-超红短枝和极矮化型桃-寿星桃为试材,对其不同生长期叶片中生长素（IAA）、脱落酸(ABA)、细胞分裂素(CTK)、赤霉素(GA)的含量与树体矮化和生长的关系进行了研究。结果表明,桃叶片中IAA、GA、CTK、ABA含量以及GA/ABA、IAA/ABA、IAA+GA+CTK/ABA、CTK/GA的比值在不同类型间的差异均达到了极显著水平。IAA、GA的含量以及GA/ABA、IAA/ABA、IAA+GA+CTK/ABA的比值与树体矮化程度呈负相关;CTK的含量与树体矮化程度呈显著负相关;与促进生长的激素相反,ABA含量和CTK/GA比值与树体矮化程度呈显著正相关。     

氮素对花铃期干旱及复水后棉花叶片保护酶活性和内源激素含量的影响

于2005—2006年在南京农业大学卫岗试验站进行盆栽试验, 设置正常灌水(土壤含水量为田间持水量的75%左右)和棉花花铃期土壤短期干旱处理(将正常灌水的棉花自然干旱持续8 d, 以棉株出现萎蔫症状为标准, 之后复水至正常灌水水平), 每个处理再设置3个氮素水平(0、3.73、7.46 g N pot^-1, 分别相当于0、240、480 kg N hm^-2), 研究氮素对花铃期干旱及复水后棉花叶片内源保护酶活性和内源激素含量的影响。结果表明, 花铃期短期干旱显著降低棉花叶片凌晨叶水势。在干旱结束时, 干旱处理棉花叶片可溶性蛋白含量与过氧化氢酶(CAT)活性显著降低、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性提高、丙二醛(MDA)含量增加, 内源脱落酸(ABA)和生长素(IAA)含量升高、细胞分裂素(ZR)和赤霉素(GA)的含量降低, ZR/ABA、IAA/ABA、GA/ABA均降低, 其叶片净光合速率(P_n)亦显著低于正常灌水处理。花铃期土壤干旱下施氮可提高可溶性蛋白含量、SOD与POD活性, 以240 kg N hm^-2最有利于提高棉花叶片P_n, 该处理CAT活性最高, MDA含量最低; ABA含量最低, 而ZR、IAA、GA的含量以及ZR/ABA、IAA/ABA、GA/ABA最高。施氮不足(0 kg N hm^-2)或过量(480 kg N hm^-2)均表现出相反的趋势。到复水后第10天, 干旱处理棉花叶片的内源保护酶活性可迅速恢复到正常灌水水平, 其MDA含量与正常灌水处理的差异较小; 但其ABA含量明显低于正常灌水处理, ZR、IAA、GA含量以及ZR/ABA、IAA/ABA、GA/ABA却显著高于正常灌水处理。并且施氮有利于提高复水后干旱处理棉花叶片的内源保护酶活性, 降低细胞膜脂过氧化程度, 降低ABA含量, 增大ZR、IAA、GA含量以及ZR/ABA、IAA/ABA、GA/ABA, 相比而言, 复水后以480 kg N hm^-2最有利于提高棉花叶片P_n。     

油棕抗寒性与内源激素的关系

为研究油棕抗寒性与内源激素的关系,人工设置温度梯度,模拟Logistic方程,求取低温半致死温度,鉴定抗寒性,采用ELISA技术测定自然降温过程中内源激素的含量。结果表明,4个品种低温半致死温度分别为-4.1℃(T1)、-0.92℃(T2)、-2.89℃(T3)、2.18℃(M1),抗寒能力为T1＞T3＞T2＞M1。自然降温过程中,从26℃降到18℃,IAA、GA、CTK、ABA含量基本不变,低于18℃后,IAA、ABA含量显著增加,GA含量稍有增加,CTK含量降低,ETH含量则变化不规律;ABA/CTK比值升高,ABA/IAA、GA/IAA、CTK/IAA、ETH/IAA比值先升高后降低。抗寒性高的品种,IAA、ABA含量高,IAA/ABA、IAA/ETH、GA/ETH、CTK/ETH、ABA/ETH比值高,表明油棕叶片IAA和ABA含量的增加利于提高抗寒力。     

干旱对棉花主茎叶片内源激素含量与平衡的影响

以鲁棉研28为试验材料,设置了干旱(土壤相对含水量RWC60%)和对照(RWC同常规棉田)2种处理,采用酶联免疫吸附法测定棉花主茎叶内源激素的含量。结果表明,2种处理下ZR含量变化呈单峰曲线,干旱出现的峰值极显著高于对照,但晚于对照;干旱处理下GA3含量出现2次峰值,说明较早进入生殖生长期;IAA含量的变化趋势差异不明显,干旱使中期叶片IAA含量显著提高;干旱处理下ABA含量前期出现一较高峰值,中后期缓慢上升,促进早衰。另外,干旱也改变了棉花主茎叶片ZR/ABA、GA3/ABA、IAA/ABA和(ZR+GA3)/ABA的动态平衡。干旱使ZR在功能期发挥作用的时间延长;GA3/ABA在激素平衡互作中关系密切;干旱处理下IAA/ABA前期较低,中后期升高,说明水分缺乏并不影响IAA和ABA在棉花生育后期发挥重要生理作用。     

低温促进白菜开花的效应分析

为了研究低温对白菜开花的效应,以普通白菜品种杭州油冬儿为试材,研究了萌动种子和幼苗低温处理对白菜开花及处理过程中可溶性糖、淀粉、可溶性蛋白质和内源激素含量的变化.结果表明,无论萌动种子还是幼苗低温处理都促进白菜植株开花;处理过程中,萌动种子与幼苗植株叶片的可溶性糖含量均升高,淀粉和可溶性蛋白质含量均下降,总的C/N值升高;萌动种子低温处理后植株的GA_3、IAA含量升高,而ABA含量下降,同时GA/ABA、IAA/ABA的值也升高,而GA/IAA的值却先下降后上升;幼苗低温处理使植株的GA_3、IAA和ABA三者的含量均升高,而且GA/ABA、GA_3/IAA,IAA/ABA的值也都升高.说明GA_3,IAA相对含量的增加有利于白菜的开花.     

施钾对棉花苗期叶片内源激素与氧自由基代谢的影响

在大田条件下,研究了钾素对棉花苗期叶片内源激素与氧自由基代谢的影响。结果表明,施钾有利于提高棉花功能叶片中生长素(IAA)、玉米素核苷(ZR)、赤霉素(GA3)的含量,降低脱落酸(ABA)的含量,有利于提高IAA/ABA,ZR/ABA,GA3/ABA之比,延缓棉花功能叶片的衰老。同时,适量施钾肥有利于提高棉花叶片中SOD活性,降低POD活性,减少过氧化物的产生和累积,有利于降低MDA含量,减轻活性氧对细胞膜的伤害。但过量施钾对氧自由基代谢不利。     

不同光质对矮生黄瓜幼苗内源激素的影响

为研究不同光质对矮生黄瓜幼苗内源激素的影响,进而对矮生黄瓜的矮化机理进行初步探讨。通过对蔓生黄瓜129和矮生黄瓜D0462覆盖白、蓝、红色滤膜获得不同光质,利用高效液相色谱法测定不同光质处理后的叶片和下胚轴中赤霉素(GA3)、吲哚乙酸(IAA)和脱落酸(ABA)的含量。结果表明,蓝光处理后,D0462叶片和下胚轴中GA3、IAA含量显著或极显著低于白光和红光,而ABA含量极显著增高;D0462的GA3、IAA含量极显著低于129,ABA含量极显著高于129;D0462下胚轴中GA3/ABA、IAA/ABA、(GA3+IAA)/ABA的比值极显著低于白光,同时也极显著低于129。综合结果可知,蓝光可能是导致矮生黄瓜D0462矮化的原因。     

贮藏条件及回湿处理对白皮松种子内源激素含量的影响

采用硅胶法对白皮松种子进行脱水处理,并将获得的各含水量的种子(7.27％(国家标准安全含水量)、4.14％、3.19％和2.18％)在室温下贮藏4个月,同时,以7.27％的种子低温贮藏为对照,研究贮藏条件及回湿处理对白皮松种子内源激素含量的影响.结果表明:(1)在种子脱水过程中,随着种子含水量的降低,其GA3和ZR含量降低,IAA和ABA含量呈先升高后降低的趋势；当含水量由7.27％降到4.14％时,GA3含量大幅下降,而ABA含量大幅升高；超干种子的GA3和ZR含量及GA3/ABA和ZR/ABA的比值均低于对照；(2)经回湿处理的种子与未回湿相比,其GA3、IAA和ZR含量及GA3/ABA和ZR/ABA比值均有所升高.其中,含水量为3.19％的种子其GA3及ZR含量极显著提高,且分别比对照提高81.3％和35.8％；而回湿处理的种子其ABA含量则下降.可见,虽然GA3及ZR在超干贮藏后其含量降低,但回湿处理后却能极显著提高,从而有效提高发芽能力,这为白皮松种子超干贮藏提供了可能性.     

烯效唑干拌种对小麦分蘖期间内源激素及糖氮比的影响

为了探明烯效唑干拌种对小麦分蘖期间内源激素及糖氮比的影响,本试验以小麦品种绵阳26为材料,采用间接酶联免疫吸附法和作物生理研究方法对其进行了研究。结果表明：烯效唑处理提高了分蘖节内ZT含量和ZT/IAA、ZT/ABA、IAA/ABA、GA/ABA比值,降低了ABA含量;在分蘖前期降低了IAA和GA含量,分蘖进入两极分化阶段IAA和GA含量升     

1-MCP和乙烯利处理对马兰头货架品质的影响

以马兰头为试材,研究0.5μL/L的1-MCP和0.1 g/L的乙烯利处理对马兰头常温(20±1)℃货架品质的影响。结果表明,常温货架期间,0.5μL/L的1-MCP处理可保持马兰头叶片中较高的叶绿素含量,延缓可溶性蛋白、VC、h°值以及还原糖含量的下降,抑制失重率的上升和游离氨基酸的积累,从而提高了马兰头的贮藏品质,延长其货架期至105 h;而0.1 g/L乙烯利处理促进马兰头叶片失重率的上升、游离氨基酸的积累,加快VC、还原糖及叶绿素含量的下降,货架期提早结束。     

Expression of Stay-Green encoding gene (BoSGR) during postharvest senescence of broccoli

Degreening caused by chlorophyll degradation is the most important feature that determines postharvest loss of quality in broccoli. Chlorophyll molecules are assembled to several thylakoid proteins, from which chlorophylls must be released in order to be catabolized. Stay-Green (SGR), a chloroplast-located protein, specifically interacts with light harvesting complex subunits helping toward their destabilization and to the release of chlorophylls. In this work, a fragment of a gene encoding a SGR from broccoli (BoSGR) was cloned. The expression of BoSGR was analyzed and detected an important increment during postharvest senescence, simultaneously with chlorophyll degradation. In order to analyze the effect of different growth regulators, different groups of broccoli heads were treated with cytokinins, ethylene and 1-MCP. Cytokinins and 1-MCP delayed the increment of BoSGR expression whereas ethylene accelerated the process. In addition, several postharvest treatments that delay degreening in broccoli florets were applied to evaluate their effects on BoSGR expression. Samples treated with modified atmosphere, hot air, UV-C or white lights showed a delay in chlorophyll degradation and degreening. In most cases, the treatments also delayed the increment of BoSGR expression during senescence, reaffirming the relationship between the expression of this gene and chlorophyll degradation.     

Changes in activities of cell wall hydrolases during ethylene-induced ripening in banana: effect of 1-MCP,ABA and IAA

Softening during ripening in climacteric fruit is generally attributed to degradation in cell wall assembly, particularly the solublization of pectin. These changes could involve increased activities of various cell wall hydrolases. Their activity is believed to be regulated by ripening-related hormones and/or other signal molecules. Activities of pectin methyl esterase (PME), polygalacturonase (PG), pectate lyase (PL) and cellulase in banana cv. dwarf cavendish fruit were measured over a period of 7 days after ripening was initiated with ethylene. Effects of treatments with 1-methylcyclopropene (1-MCP), abscisic acid (ABA) and indole acetic acid (IAA) on activities of these hydrolases were measured in order to help elucidate their roles during banana ripening. Ethylene stimulated activities of all four enzymes, at best differentially. 1-MCP and IAA suppressed the ethylene effects. ABA stimulated activities of all hydrolases except polygalacturonase. ABA stimulation was most evident for pectate lyase. Thus ethylene plays a major role in up-regulating the activities of various cell wall hydrolases. In contrast IAA suppresses their activity. ABA can enhance softening with or without ethylene.     

UV-C复合热处理或1-MCP处理对西兰花保鲜效果的研究

以采后西兰花为试材,研究UV-C与热处理、1-MCP单独或复合处理对西兰花采后冷藏及货架期间品质的影响。结果表明,在冷藏(0℃)前,采用UV-C照射与热处理、1-MCP单独或复合处理,对西兰花在冷藏65 d和货架5 d期间的感官品质和营养成分均具有较好的保鲜效果。其中以0.25μL/L的1-MCP熏蒸20 h及复合UV-C照射600 s对西兰花的护绿、抑制花蕾开放以及保持VC和叶绿素含量的效果显著好于其他处理,感官品质评价总分较高;45℃热水处理5 min及复合UV-C照射处理对控制西兰花腐烂率的效果较好。     

1-Methyl cyclopropene extends postharvest life of spinach leaves

Senescence of detached spinach leaves either untreated or treated with 0.1 or 1.0 μL L^?1 1-MCP has been investigated. 1-MCP treated leaves had higher chlorophyll content and photosystem II potential quantum yield (Fv/Fm) and lower solute leakage than untreated leaves after storage in darkness at 23 °C for 6 d, indicating a delay of senescence. Ethylene production was increased in spinach supplemented with 1-MCP after 3 d storage and then declined to the rates of untreated leaves. 1-MCP treated spinach had higher ascorbic acid and glutathione concentrations, and a low oxidised/reduced ratio for both antioxidants. Accumulations of ammonium and protein degradation were reduced by 1-MCP. The results presented here indicate that inhibition of ethylene sensitivity can be successfully used to extend the postharvest life of spinach leaves.     

Effect of 1-methylcyclopropene (1-MCP) treatment on sweet basil leaf senescence and ethylene production during shelf-life

The effect of 1-methylcyclopropene (1-MCP) on shelf-life and postharvest quality of sweet basil detached leaves was examined. Treatment with 0.2, 0.4 and 0.6 g m⁻³ 1-MCP for 8 h was conducted at 15 °C in the dark. After the treatment the leaves were packed in polyethylene bags then sealed and stored at 20 °C. All 1-MCP concentrations significantly increased the shelf-life of leaves compared to the untreated control, and leaf weight loss with 1-MCP treatment was minimal. 1-MCP treatment significantly retarded the degradation of chlorophyll and protein content of detached leaves during storage and decreased leaf ethylene production. 1-MCP treatment also significantly retarded the decrease of volatile oil percentage in detached leaves during storage compared to the control. Among 1-MCP concentrations, 0.4 g m⁻³ resulted in the maximum shelf-life as well as improved postharvest quality of the leaves. The results clearly indicate that a single treatment with 1-MCP may provide a feasible technique for extending the shelf-life and maintaining higher volatile oil percentage of sweet basil leaves.     

1-MCP对果实采后生理变化的影响

对1-MCP作用效应的影响因素进行阐述,同时从果实风味、硬度、可滴定酸、可溶性固形物、果皮叶绿素、采后生理病害、乙烯生成和呼吸速率等几个方面描述1-MCP对果蔬采后贮藏保鲜的作用效果.     

The effects of 1-methylcyclopropene on the shelf life of minimally processed leafy asian vegetables

The effect of 1-methylcyclopropene (1-MCP) on shelf life and the ethylene sensitivity of detached leaves from six leafy asian vegetables (Chinese mustard, choy sum, garland chrysanthemum, mibuna, mizuna and tatsoi) commonly used in minimal processing was examined. All vegetables studied were significantly affected by the presence of 1 μl/l ethylene. This reduction was primarily due to yellowing except in mizuna and mibuna. In the absence of ethylene, 1-MCP treatment only increased shelf life for mizuna and tatsoi (21 and 67% increase, respectively). In contrast, 1-MCP treatment in the presence of ethylene significantly protected Chinese mustard, choy sum, garland chrysanthemum and tatsoi. 1-MCP may, therefore, be ideal for use on minimally processed leafy asian vegetables in situations of co-storage or co-retail with ethylene-producing commodities.     

1-MCP对贮藏酥梨品质的影响

为了延长贮藏酥梨货架期品质,以酥梨果实为试材,研究了0.5 μL/L和1.0 μL/L 1-MCP 2种浓度对通风库贮藏酥梨货架期品质的影响。处理果实与对照相比,能较好维持原有外观品质;处理果实呼吸强度和乙烯释放量比对照都有所降低。0.5 μL/L处理效果较明显,果实呼吸强度最低比对照降低24%;1 μL/L处理乙烯释放量最低比对照降低53%,0.5 μL/L处理比对照最低下降了31%。1-MCP处理能延缓果实硬度和可溶性固形物的下降,0.5 μL/L处理果实硬度平均比对照高4.6%,1.0 μL/L处理果实硬度平均比处理高8.6%;0.5 μL/L处理果实可溶性固形物含量与对照有明显差异,最低可下降13%。综合来看,0.5 μL/L对延长地下通风库酥梨货架期有较好的效果。