不同苗龄期黄瓜根系生理生化及形态指标的研究

The Study on Root Physiological and Biochemical Characteristics of Cucumber Plug Seedlings in Different Seedling Stages

为了确定黄瓜秧苗适宜的定植时间,为黄瓜穴盘苗的生产提供科学依据,以‘津育五号’黄瓜为试验材料,采用穴盘育苗方法,研究不同育苗时间对黄瓜根系的形态及生理生化指标的影响。这些指标包括根系的形态、根冠比、根系活力、根系保护酶活性及根系结构。根据直径将黄瓜根系分为细根(<0.05mm),中根(0.05～0.45mm)和粗根(>0.45mm)。结果表明,三叶一心处理秧苗各直径根系的根长和根表面积虽然在绝对数量上占优势,但是吸收能力较强的细根的根长和根表面积占总根系的比例均低于两叶一心处理和一叶一心处理,吸收能力较差的中根比例明显高于两叶一心处理和一叶一心处理。相对于其他2个处理,三叶一心处理的秧苗鲜重增加,根冠比减小,根系活力降低,SOD、POD活性均升高;秧苗中导管数目增多,但单个导管直径相对较小。总之,一叶一心秧苗和两叶一心秧苗的各项指标差异不大,均可进行秧苗的定植;三叶一心秧苗由于秧龄过大,已不适宜作为适龄苗龄进行定植。

The aim of this study was to determine the appropriate transplanting time of the cucumber seedlings and provide scientific basis for practical use. ＇Jinyu 5＇ was used as material to study the root physiological and biochemical characteristics in different growth stages, by the method of plug seedling culture. These characteristics included root morphology, the ratio of root/shoot, root vigor, activities of protective enzymes of root and root structure. The root system was classified into fine roots （〈 0.05 mm）, middle roots （0.05-0.45 mm） and coarse roots （〉 0.45 mm） according to root diameter. Compared to the seedlings with one and two leaves, the results showed that the root length and surface area with three leaves were longer and bigger for roots with different diameters. However, the ratio of fine roots with stronger absorbing capacity of seedlings with three leaves was lower than those of seedlings with one and two leaves while the ratio of middle roots was obviously higher than those of seedlings with one and two leaves. Additionally, compared with the other two treatments, for seedlings with three leaves, the fresh weight of seedlings increased, the ratio of root/shoot decreased, root activity reduced, while SOD and POD activities increased. The number of vessel tubes of seedlings with three leaves was increased but a single vessel diameter was decreased. In conclusion, the current study indicated that seedlings with one leaf had no significant difference from seedlings with two leaves, and both could be used for transplanting, while seedlings with three leaves were not suitable for transplanting due to over growth.