Veselova Tatiana V, Veselovsky Vladimir A, Obroucheva Natalie V
Biology Faculty, Lomonosov Moscow State University, 119991, Moscow, Russia.
Biology Faculty, Lomonosov Moscow State University, 119991, Moscow, Russia.
Plant Physiol Biochem. 2015 Feb;87:133-9. doi: 10.1016/j.plaphy.2014.12.019. Epub 2014 Dec 26.
The deteriorative reactions underlying seed aging, namely, lipid peroxidation and non-enzymatic carbohydrate hydrolysis, were studied in pea seeds differing in quality. Aging air-dry seeds were subdivided to three fractions using the application to individual seeds of room temperature phosphorescence. These fractions were strong seeds (fraction I) producing normal seedlings, weak seeds (fraction II) producing mainly abnormal seedlings, and dead seeds (fraction III). Enzymatic processes cannot operate in dry seeds due to the absence of free water, and thus an analytical method was needed that does not require the addition of water. The content of lipid peroxidation products was similar in both strong and weak seeds; this excluded the possibility that lipid peroxidation induced the transition of strong to weak seeds during early aging. Lipid peroxidation was activated only in dying seeds. However, glucose content in weak seeds was much higher than in strong seeds, suggestive of non-enzymatic hydrolysis of carbohydrates, probably of oligosaccharides, which utilized bound water in air-dry seeds. This process resulted in lowered water content in weak seeds. Therefore, associated with deterioration of air-dry seeds during early aging is the non-enzymatic hydrolysis of carbohydrates, whereas lipid peroxidation is not the decisive event.
对品质不同的豌豆种子中种子老化所涉及的劣化反应,即脂质过氧化和非酶促碳水化合物水解进行了研究。通过对单个种子应用室温磷光,将老化的风干种子分为三个部分。这些部分分别是能产生正常幼苗的强种子(部分I)、主要产生异常幼苗的弱种子(部分II)和死种子(部分III)。由于干燥种子中没有自由水,酶促过程无法进行,因此需要一种无需加水的分析方法。强种子和弱种子中脂质过氧化产物的含量相似;这排除了脂质过氧化在早期老化过程中导致强种子向弱种子转变的可能性。脂质过氧化仅在即将死亡的种子中被激活。然而,弱种子中的葡萄糖含量远高于强种子,这表明存在碳水化合物的非酶促水解,可能是寡糖的水解,其利用了风干种子中的结合水。这一过程导致弱种子中的水分含量降低。因此,在早期老化过程中,与风干种子劣化相关的是碳水化合物的非酶促水解,而脂质过氧化并非决定性事件。