在大白菜叶球形成过程中其叶球结构有一系列的变化。早熟品种往往外叶数较少,而球叶数亦较少;晚熟的品种往往外叶数较多,球叶数亦较多。直筒形的早熟种,往往外叶数较少,球叶数亦较少,在结构上多为“叶重型”;卵圆形的晚熟种,往往外叶数较多,在结构上为“叶数型”。在叶数型与叶重型之间有许多中间类型。 不同品种类型之间,同一叶球的不同叶位之间,生化成分有很大的差异。叶的中肋榨出液,其可溶性圆形物的含量,都是外叶较少,球叶较多,越到叶球的“心叶”,含量也越高。 过氧化物酶的活性,在结球期的叶片中是外叶较高,球叶较低(至于中肋的活性,则有相反的趋势),叶片中的活性又比中肋的高,而且无论是叶片还是中肋都是结球期比莲座期低。多酚氧化酶的活性是外叶较高,球叶较低。不同叶位的中肋榨出液的电导度也是外叶较高,球叶较低,但球叶的叶位之间差异不大。 There are a series of changes in the structure of leaf lobes during the formation of Chinese cabbage leaf. Early varieties tend to have fewer outer leaves and fewer bulbous leaves. Late-maturing varieties tend to have more outer leaves and more bulbous leaves. Straight-shaped early-maturing species, often less outer leaves, the number of leaves is also less, mostly in the structure of “leaf-heavy”; oval late-maturing species, often more outer leaves, the structure of “leaves Number type. ” There are many intermediate types between leaf number and leaf weight. Between different types of species, the same leaf lobes between different leaf positions, biochemical composition are very different. Ribs in the squeeze out of the liquid, the content of soluble round, are less outer leaves, more leaf balls, the more to the leaf “heart” leaves, the higher the content. Peroxidase activity was higher in the outer leaves than in the midrib at the node of the cotyledon and lower in the cotyledons (as opposed to the activity of the midrib), and the activity in the leaves was higher than that in the midrib Both the leaf blade and the midrib are lower than the rosette stage. Polyphenol oxidase activity is higher outer leaves, lower leaves. The conductivity of the medium ribbed extracts at different leaf positions was also higher in the outer leaves and lower in the leaf leaves, but there was no significant difference between the leaf positions of the leaves.