柑橘果实油斑病砧穗特异性的FTIR研究

【目的】采用分子光谱技术探讨哈姆林果实油斑病砧穗特异性调控的分子生理机制，为提出果实油斑病综合防治措施，有效降低柑橘果实油斑病发生提供理论基础。【方法】利用果实油斑病发生率及发生程度有显著差异的11年生的3种砧木哈姆林甜橙植株，研究柑橘果实油斑病敏感期砧木对哈姆林甜橙果实油斑病发生率和发生程度的影响及哈姆林甜橙植株叶片和果实傅立叶红外光谱（FTIR）图谱变化。【结果】砧木对哈姆林甜橙果实油斑病发生率和发生程度的影响显著不同。其中，哈姆林/枸头橙果实油斑病发生程度（DO）最高；哈姆林/李齐16-6枳果实油斑病发生率（RO）最高；而哈姆林/印度酸橘有较高的RO值，最低的DO值。FTIR分析结果表明，夏季高温期3种砧木的哈姆林甜橙叶片在3420、2927、1625和1069 cm-1处波峰分别代表了碳水化合物的合成和运输、叶片细胞壁中的组织成分变化、蛋白质稳定程度和叶片内膜质过氧化平衡破坏程度，以枸头橙为砧的哈姆林甜橙植株叶片吸收峰强度最高受影响较小，以印度酸橘为砧的次之，以李齐16-6枳为砧哈姆林甜橙叶片受影响程度最大。相反，果皮红外光谱以印度酸橘和枸头橙为砧的哈姆林甜橙果皮受高温胁迫影响显著高于以李齐16-6枳为砧的哈姆林甜橙果皮。同时，3种砧木果实油斑病发生程度和发生率分别与其果皮和叶片红外光谱变化趋势一致。【结论】柑橘果实油斑病发生率高低可能跟叶片高温逆境响应机制有关，而果实油斑病发生程度高低直接与果皮代谢相关，通过分析夏季高温期叶片和果皮FTIR分别预测本年度油斑病发生率和发生程度是可行的。同时，叶片和果皮FTIR分析有利于揭示柑橘果实油斑病砧穗特异性分子生理机制。

Analysis of the Specificity of Rootstock and Scion Combinations of ‘Hamlin’ Sweet Orange Related to Fruit Oleocellosis by FTIR

【Objective】Fourier transform infrared (FTIR) spectrometry, which is accurate, simple and efficient, with high resolution, was used to investigate the molecular physiological mechanisms of the specificity of rootstock and scion combinations of ‘Hamlin’ sweet orange [Citrus sinensis (L.) Osbeck cv. Hamlin] related to on-tree oleocellosis.【Method】The influence of ‘Hamlin’ sweet orange on Goutouchen sour orange [C. aurantium (L.). GT], Rich trifoliate 16-6 [P. trifoliate (L.). LC] and Cleopatra mandarin [C. reticulate (L.). IO] on rates of oleocellosis (RO) and degree of oleocellosis (DO) were measured at harvest stage. And the leaf and fruit peel FTIR spectroscopy of ‘Hamlin’ sweet orange on GT, LC and IO were also determined at the sensitive period of on-tree oleocellosis.【Result】The results showed that rootstocks had a significant influence on RO and DO of ‘Hamlin’ sweet orange fruits, and the fruits of ‘Hamlin’ sweet orange on GT and LC had the highest DO and RO, respectively. In contrast, the fruits of ‘Hamlin’ sweet orange on IO had the lowest DO and second higher RO. And the leaf absorption peak intensity (API) at 3420, 2927, 1625 and 1069 cm-1 of ‘Hamlin’ sweet orange on GT, IO and LC decreased in order. The above results showed that the influence of high temperature on leaf carbohydrate synthesis and transport, cell walls composition, protein stability and leaf membrane lipid peroxidation balance of ‘Hamlin’ sweet orange on GT were minimal, next was Hamlin sweet orange on IO, and ‘Hamlin’ sweet orange on LC were maximum. However, the API of peel FTIR of ‘Hamlin’ sweet orange on IO and GT was significantly lower than that of ‘Hamlin’ sweet orange on LC. Whilst, the changes of RO and DO were consistent with leaf FTIR and fruit peel FTIR, respectively.【Conclusion】 RO may be related to the response of citrus leaves to high temperature stress, in contrast, DO is directly related to fruit peel metabolism. And it is feasible to predict RO and DO by leaves and peels FTIR analysis, respectively. At the same time, leaf and peel FTIR analysis is helpful to reveal the stock-scion specific molecular and physiological mechanisms of on-tree oleocellosis.