Effect of soaking seeds in diethyl aminoethyl hexanoate on the promoting germination and seedling establishment of sweet melon (Cucumis melo L.) during the seedling stage

Owing to the diversity in melon varieties, many seeds have thick coats and wax layers, which affect seed germination to some extent. The seed kernels contain a certain concentration of triglycerides and fatty acids, and the oxidation of these biomolecules during seed storage can observably shorten the seed life and reduce germination ability. This research was carried out to examine the effects of soaking seeds in different concentrations of diethyl aminoethyl hexanoate (DA-6) on the germination and growth of sweet melon seeds. The treatment groups were treated with 20 mg · L⁻¹ (T1), 60 mg · L⁻¹ (T2), 180 mg · L⁻¹ (T3) and 360 mg · L⁻¹ (T4) concentration of DA-6, and the control group T0 (CK, 0 mg · L⁻¹ of DA-6). The results showed that DA-6 treatment at a concentration of 60 mg · L⁻¹ markedly promoted the seed germination rate, at 180 mg · L⁻¹ it increased the height and leaf width of sweet melon plants and at 360 mg · L⁻¹ it improved the stem thickness of seedlings. Further analysis revealed that at 60 mg · L⁻¹ there was increase in the length of the seedling leaves, which increased by 19.86% compared with CK. At the same time, DA-6 soaking has a significant regulatory effect on the chlorophyll content, peroxidase activity and malondialdehyde content of sweet melon leaves during the seedling stage. The most significant effect on increasing the chlorophyll and peroxidase content of sweet melon leaves as well as reducing the malondialdehyde content was found in treatment with 60 mg · L⁻¹ DA-6. Analysis of the correlation among the physiological, biochemical and morphological indicators of melon seedlings showed a significant relationship between the content of the physiological indicators in melon seedling leaves and the establishment of their morphology. Through comprehensive analysis, soaking seeds in different concentrations of DA-6 can effectively regulate the germination, morphological characteristics and leaf physiological substances of sweet melon seedlings during the seedling stage. Through these effective regulations, the vigorous growth of sweet melon seedlings during the seedling stage can be promoted. Soaking seeds in 60 mg · L⁻¹ concentration of DA-6 was found to be the most beneficial for promoting the germination and growth of sweet melon seeds.