【作者】 吕静；

【导师】 张玉星；

【作者基本信息】 河北农业大学 ， 果树学， 2002， 硕士

【摘要】 水杨酸（SA）和茉莉酸甲酯（MJ）是植物体内普遍存在的内源信号分子和新型植物激素，在植物的许多生理反应和基因表达方面发挥着重要的调控作用。果实成熟和衰老是果实发育的最后阶段，该阶段直接关系到品质形成和贮藏保鲜。研究SA和MJ在果实成熟衰老中的调控机制，旨在进一步揭示和完善果实发育的基础理论，同时为有效地调控果实成熟衰老的进程、改善果实品质和贮藏性能提供依据。 本试验以新红星和红富士苹果及鸭梨为试材，利用果实圆片培养的方法研究了SA和MJ在果实成熟衰老中的调控机制、二者对果实品质的影响及SA与MJ的相互作用关系，主要研究结果如下： 1．外源MJ可显著降低果实圆片中内源SA的含量。且内源SA水平随外源MJ处理浓度的提高呈规律性下降，其中5×10^-1mol·L^-1MJ对新红星苹果和鸭梨中内源SA的抑制作用最强，5×10^-3mol·L^-1MJ对红富士苹果中内源SA的抑制作用最强。结果表明：MJ作为衰老的促进剂，通过降低SA的含量来促进果实成熟衰老过程。 2．外源SA可抑制MJ的生物合成过程。SA显著降低红富士、新红星苹果和鸭梨果实圆片中LOX和AOS的活性。随SA处理浓度的增加，三者果肉中LOX、AOS的活性逐渐降低。当SA的浓度为2mmol·L^-1时，三者果肉中LOX、AOS的活性最低。且SA对AOS的抑制作用明显强于对LOX的抑制程度。从试验可得出SA可能主要通过抑制AOS的活性来抑制果实MJ的生物合成。SA降低LOX、AOS活性，充分说明了SA一方面是通过保护细胞膜系统起到防衰保鲜的作用；另一方面是SA可以通过调控与果实衰老有关的内源激素MJ的生物合成过程，来延缓果实成熟衰老，达到贮藏保鲜作用。 3．外源MJ可促进其自身的生物合成过程。5×10^-1mol·L^-1～5×10^-4mol·L^-1MJ处理可显著提高果肉中的LOX、AOS活性。但不同的MJ浓度对新红星、红富士和鸭梨果实圆片中LOX、AOS活性的处理效应不同。对于鸭梨来讲，在6个MJ浓度中以5×10^-6mol·L^-1MJ对LOX的促进效果最显著，LOX的活性较对照增加60．87％；而5×10^-5mol·L^-1MJ对红富士的LOX促进作用最强，与对照相比，LOX活性增加48．78％；MJ对新红星的最适处理浓度为5×10^-1mol·L^-1，与对照相比，LOX活性增加了22．73％。5×10^-6mol·L^-1MJ对鸭梨中AOS的促进效果最显著，比对照增加38．10％：5×10^-5mol·L^-1MJ对红富士、新红星果实中的AOS促进作用最强，与对照相比，AOS活性分别增加53．85％、60．00％。试验结果进一步说明了MJ通过提高LOX和AOS的活性来调控自身的含量以促进果实的成熟衰老过程。 果实衰老中水杨酸和茉莉酸甲酌的效应及其关系研究 4．5 X 10－’。。l·L‘～5 X 10－‘。。l·L‘的外源 m提高果实中 PG的活性。表明MJ通过提高PG的活性来促进果实的成熟软化过程，加速了果实衰老。 5．5 X 10－’。OI，L－‘～5 X 10－’。OI·L－‘的外源 m提高果实中 PPO的活性。其中5X10－mol·L‘的MJ显著的提高了新红星和红富士苹果果实PPO的活性，对鸭梨果实来讲，5 X 10’mol·L－’的 MJ处理效果最显著。说明饲J会加速果实的褐变从而影响到果实的外观、鲜食和贮藏品质。 6．SX 10－’。of·L－‘～SX10－’mol·L－’的外源＊提高果实中叩L的活性。随w 7处理浓度的升高，鸭梨、红富士果实圆片中PAL的活性逐渐增加。在6个w浓度中以 5 XIO‘mo·L－‘的 MJ对两者 PAL活性的促进效果最显著。 7．SX！0’。。IL’～SX 10‘mol·L‘的外源饲J抑制 POD的活性。随 MJ处理浓度的增加，果实中POD活性逐渐降低。 8．0．002 mmol·L－‘～0．2。of·L－’SA可以抑制鸭梨、新红星和红富士苹果中PG的活性，表明SA可以延缓果实成熟和软化过程。 9．外源SA降低果实中W 的活性。随SA处理浓度的增加，新红星苹果和鸭梨果实圆片中什 的活性逐渐降低。对新红星、红富士苹果和鸭梨果实来讲，当SA的浓度分别为2、0．002、0．2。。OI·卜’时，果实圆片中PO的活性最低。因此SA可防止褐变的发生，延缓果实品质的劣变。 m．0．002。OI·卜’～0．2＿OI·L’的外源趴降低果实中mL的活性。SA对三者的影响趋势相似。SA处理对鸭梨、新红星、红富士果实圆片中PAL活性抑制程度最强的浓度分别为 0．002、0．002、0．2 m。of·Ld。 11．0．002～2。OI·L－‘的外源犯提高果实中 POD的活性。SA对三者的影响趋势相似。随SA处理浓度的增加，果实中POD活性逐渐增加。当SA为Zmmol·L‘浓度时，对红富士和鸭梨果实中POD活性的促进效果最明显，而0．2 nunol·L它A对新红星果实中POD活性促进作用最强。表明SA可通过提高保护酶的活性来延缓果实衰老。 12．新红星、红富士苹果果实中种子中LOX的活性最高，极显著高于果实的其它部位：其次是果皮的＊X活性较高；然后是果肉中的＊X，而以果心中的mx更多还原

【Abstract】 Salicylic acid (SA) and Methyl Jasmonate (MJ) are important signal substances and also newly found plant hormones, which play a crucial role in regulation of physiological action and expression of genes in plants. Ripening and senescence occur dramatically during later stage of fruit development, which is closely associated with storage quality. It is helpful to further reveal the mechanism of fruit development so that the physiological and biochemical effects of SA and MJ on fruit ripening and senescence could be explained. Furthermore, the study on this respect could provide a theoretical basis for ripening control, quality improvement and extension of storage life.Two cultivars of apple, "Starkrimson" and "Red Fuji", and one variety of pear of "Yali" pear were used to examine the regulating effects of SA and MJ on fruit senescence and quality, as well as the relationship between SA and MJ by means of flesh discs culture. The main results were as follows:1. The external MJ greatly decreased the content of endogenous SA in fruit discs. SA content decreased gradually as MJ concentrations increased from 5X 10"7 mol ?L"1 to 5X 10~3 mol ?L"’. SA content in "Starkrimson" apple and "Yali" pear reached the lowest point when fruit discs were treated with MJ at 5X lO^mol ?L"1. SA content in "Red Fuji" fell to the lowest point when fruit discs were treated with MJ at 5 X 10~3 mol?L"’. These results indicated that MJ accelerated the process of fruit senescence by decreasing SA content.2. SA inhibited biosynthetic process of MJ because it remarkably inhibited LOX and AOS activities in fruit discs. LOX and AOS activities decreased gradually with increase of SA concentration and reached the lowest level when fruit discs were treated with SA at 2 mmol ?L"1. Furthermore, the degree of SA inhibition from AOS was higher than that of SA from LOX. This meant that inhibition of SA from AOS activity was responsible for the inhibition of SA from the biosynthesis process of MJ. It could be concluded that SA was able to delay fruit senescence by protecting cell membrane system; on the other hand, SA could control the biosynthetic process of MJ, thus delaying fruit ripening and senescence.453. The external MJ accelerated the biosynthetic process of endogenous MJ. MJ remarkably increased LOX and AOS activities in fruit discs. LOX activities in "Red Fuji", "Starkrimson" apple and "Yali" pear discs achieved the lowest level when fruit discs were treated with MJ at 5X 10"5mol ?I/1, 5X 10’7mol ?I/1 and 5X lO^mol ?L’1 respectively with corresponding reduction by 48.78%, 22.73% and 60.87% in contrast to that from CK. AOS activity in "Red Fuji", "Starkrimson" apples and "Yali" pear discs reached the lowest point when fruit discs were treated with MJ at 5 X 10~5 mol ?L"1, 5X 10"5 mol ?L"1 and 5X lO^mol ?L"1 respectively with corresponding reduction by 53.85%, 60.00% and 38.10% as compared with that from CK.4. The exotic MJ (5X 10"7~5X lO’Vol ?L"1) enhanced PG activity in fruit discs, which implied that MJ accelerated fruit senescence by increasing PG activity.5. The exotic MJ (5X 10~7~~5X lO^mol ?L"1) increased PPO activity in fruit discs. PPO activity in "Red Fuji", "Starkrimson" apples and "Yali" pear discs achieved the lowest level when the fruit discs were treated with MJ at 5X10"6 mol ?L"1, 5X 10"6 mol ?L’1 and 5X 10"7mol ?L"1 respectively. This showed that MJ could accelerate fruit browning and deteriorate fruit quality.6. The exotic MJ (5X 10"7~5X lO^mol ?L"1) increased PAL activity in "Red Fuji" apple and "Yali" pear discs. PAL activity in "Red Fuji" apple and "Yali" pear discs reached the highest point when fruit discs were treated with SA at 5X 10"4 mol ?L’1.7. The exotic MJ (5 X 10"7~5X lO^mol ?L"1) decreased POD activity in fruit discs. POD activity in "Red Fuji", "Starkrimson" apples and "Yali" pear discs decreased gradually with increase of MJ concentration.8. The exotic SA (0.002~0.2mmol ?L"1) decreased PG activity in fruit discs. This revealed that S更多还原