缺铁逆境下南方苹果实生苗细胞的超微结构及净同化率

The Ultra Micro-structure of the Seedling Cell of Southern Apple and Net Assimilating Rate under Adverse Circumstance for Lack of Iron

将南方苹果早翠实生苗于1.3mg/kg铁、pH5.5;0.13mg/kg铁、pH6.5;无铁,pH5.5;无铁,pH6.5;无铁,pH7.8;5个处理中培养,取其幼叶和老叶分别观察其细胞超微结构变化和新、老叶的净同化率,并测各处理中叶片、根系中含铁量。结果表明:各个铁逆境处理的苹果苗都呈现出极为明显的失绿症状,且随铁素减少和pH值升高失绿症状加重,细胞内很少看到微体,淀粉粒很小或看不到。而培养于含铁1.3mg/kg、pH5.5营养中的苹果苗其叶肉细胞中的叶绿体发育正常,并可见线粒体、微体及淀粉粒。在有效光合辐射内,正常铁植株幼叶的净同化率比缺铁处理的高2～4倍。正常含铁量及低铁处理的苹果苗的老叶净同化率基本相同,但无铁处理的较低。所有其他各处理的植株根、叶组织中含铁量只有细微的差异。

The seedling cells of Early Green in southern apple were planted in 5 kinds of culture mediums such as： 1.3 mg/kg iron, pH 5.5;0. 13 mg/kg iron, pH 6.5; no irons, pH 5.5; no irons, pH 6. 5; no irons, pH 7.8; then selected their young leaf old leaf and respectively to observe the change of cell in ultra micro-structure and the net assimi- lating rate of new leaf and old leaf, and to examine iron content in leaf and root system in all kinds of culture mediums. The result indicated that each apple seedling under adverse circumstance which lack of iron had obvious symptom that lose green extremely, and the symptom of losing green aggravated with the iron reduces and pH value rises, and seldom see tiny body in the cell, and the starch grain seldom or can＇t find. But the chloroplast and mesopHyll cell of apple seedling developed well when planting in 1.3 mg/kg iron, pH 5.5 nutrition, and could see the mitochondria, tiny body and starch grain. In the valid ray radiation, the net assimilating rate in normal iron young leaf of plant was 2~4 times higher than the ones that lack irons. Normal iron content and low iron apple seedling basically had the same assimilating rate, but it was relatively lower that had no iron deal with. In other kinds of culture mediums, iron content had slight differences in the tissue of root,