无机盐与激素混合对土沉香结香的诱导

Mechanism of Agarwood Formation under the Induction of Both Inorganic Salts and Hormones

【目的】探明无机盐与激素混合配比对土沉香结香的影响,揭示其结香机制,为促进土沉香结香奠定基础。【方法】以10年生土沉香为材料,采用均匀试验设计,以NaCl、FeSO4、CaCl2、茉莉酸甲酯和乙烯利为诱导因子,每个因子3个水平,共5种处理,分别在诱导处理后0.5、1、3、6、10个月取样,测定淀粉、可溶性糖、醇溶性浸出物含量以及木芯变色范围;利用光学显微镜观察切片组织化学变化,扫描电镜观察组织结构内含物变化。【结果】1)随诱导时间增加,各处理淀粉含量先降低后升高,降至最低值时间不同;可溶性糖含量先升高后降低,各处理均在第6个月达到峰值;2)各处理射线薄壁细胞、轴向薄壁细胞和导管内油脂类物质含量随诱导时间增加不断积累;3)木薄壁细胞内侵填物质通过导管-薄壁细胞间半具缘纹孔进入相邻导管内积累至完全堵塞;4)各处理在木芯变色横向宽度上诱导效果不佳,而在纵向上诱导效果较好、变色较长,其中处理2(0.5%NaCl+1.5%FeSO4+0.1%CaCl2+0.01%茉莉酸甲酯+0.05%乙烯利)诱导10个月的纵向变色长度达77.0 cm;5)随诱导时间增加,各处理醇溶性浸出物含量不断增加,且差异显著。【结论】1)5种诱导处理中,以0.5%NaCl+1.5%FeSO4+0.1%CaCl2+0.01%茉莉酸甲酯+0.05%乙烯利诱导效果最好,处理10个月时醇溶性浸出物含量最高,达19.07%;2)促进土沉香结香的主要诱导因子为NaCl和乙烯利,其中乙烯利起主导作用,理论上诱导土沉香结香的最佳因子组合为0.16%NaCl+0.21%乙烯利;3)结香油脂首先在薄壁细胞内形成,随后在导管和薄壁细胞内积累,导管内油脂物质积累与薄壁细胞内淀粉含量变化有关,淀粉转化为可溶性糖的能力越强,油脂积累越多,越有利于结香。

【Objective】This study explored the effects of different combinations of inorganic salts and hormones induced to agarwood and its mechanisms in Aquilaria sinensis,with the aim to effectively promote agarwood formation.【Method】Uniform test design was used to deal with ten-year-old trees.NaCl,FeSO4,CaCl2,methyl jasmonate and ethephon were selected as the induction factors,and each factor covered 3 levels,totally 5 induction treatments.The content of starch,soluble sugar,alcohol soluble extract and the discoloration range of stem wood were determined,and histochemical and inclusion changes were,respectively,observed by optical microscopy and scanning electron microscope(SEM)through wood core samples that taken 0.5,1,3,6,10 months after treated.【Result】1)With the increase of induction time,the content of starch firstly decreased and then increased,and the time to reach to the lowest value was different between different treatments.While the content of soluble sugar was opposite,which firstly increased and then decreased,and the peak values were reached all at the 6th month.2)It was found that the content of lipid substance in the ray cells,axial parenchyma cells and vessel of each treatment increased with time.3)Wood parenchyma tylosis accumulated into adjacent vessel through half bordered pit between the vessel and parenchyma cells until complete blockage.4)The effect of each treatment on the lateral discoloration range of wood core was not significant,but the length of the longitudinal discoloration was longer.The longitudinal discoloration length of treatment 2(0.5%NaCl+1.5%FeSO4+0.1%CaCl2+0.01%methyl jasmonate+0.05%ethephon)reached 77.0 cm after 10 months of induction.5)The content of alcohol soluble extract increased with time,and the differences between different treatments were significant.【Conclusion】1)Among the five induction treatments,the optimal treatment was 0.5%NaCl+1.5%FeSO4+0.1%CaCl2+0.01%methyl jasmonate+0.05%ethephon,and the content of alcohol soluble extract reached 19.07%after 10 months of treatment.2)NaCl and ethephon were the main factors to promote the aloes yield,and ethephon played a leading role.Theoretically,the optimum combination of agarwood induction was 0.16%NaCl+0.21%ethephon.3)The lipids were firstly formed in parenchyma cells and then accumulated in vessel and parenchyma cells.The accumulation of lipids in the vascular was related to the changes of starch content in the parenchyma cells,the stronger the ability of starch transformed to soluble sugar,the more lipid accumulated and the more favorable for agarwood formed.