水分胁迫下荔枝叶片过氧化物酶和IAA氧化酶活性的变化

以适应山地栽培的抗旱性较强的东刘1号和适应河边栽培的抗旱性较弱的陈紫2年生荔枝（Litchi chinensis Sonn.)实生苗为试验材料，研究了水分胁迫下叶片细胞胞质，与（细胞）壁以离子键结合和壁以共价键结合的过氧化的酶（POD）和IAA氧化酶活性的变化。结果表明：在叶片中POD主要是以与壁以离子键结合的POD存在，占总活性的51．15％－52．15％，其次是细胞胞质POD，占44．20％－44．74％，与壁以共价键结合的POD活性最低，仅占3．44％－3．65％。与POD不同，IAA氧化酶绝大多数存在于细胞胞质中，占总活性的88．93％－89．29％，其次是少量的与壁以离子键结合的IAA氧化酶，占7．32％－7．63％，与壁以共价键结合的IAA氧化酶活性最低，仅占3．39％－3．44％；2个品种间差异不明显。水分胁迫下，叶片细胞胞质以及与壁以离子键和壁以共价键结合的POD和IAA氧化酶（比）活性均上升，抗旱笥较强的品种上升的幅度均大于抗旱性较弱的品种。

Changes in Peroxidase and IAA Oxidase Activities in Litchi Leaves under Water Stress

The 2 years old seedlings of two litchi (Litchi chinensis Sonn.) cultivars differing in drought resistance, were used in this study. Chenzi grown in riverside is considered to be drought sensitive, while Dongliu No.1 grown on hills is considered to be drought resistant. Effect of water stress on the activities of cytoplasmic, ionically wall bound and covalently wall bound peroxidase (POD) and IAA oxidase in litchi leaves was studied. The results showed that: (1) The activities of cytoplasmic, ionically wall bound and covealently wall bound POD were 44 20%~44 74%,51 28%~52 15%, and 3 44%~3 65% of the total POD activity, respectively in the leaves. In contrast, the activities of cytoplasmic, ionically wall bound and covealently wall bound IAA oxidase were 88 93%~89 29%,7 32%~7 63%, and 3 39%~3 44% of the total IAA oxidase activity,respectively in the leaves. No significant differences were observed between the two cultivars. (2) Under water stress, the specific activities of cytoplasmic, ionically wall bound and covalently wall bound POD in leaves increased and that the extent of increase was greater in drought resistant cultivar than in drought sensitive one. The results of IAA oxidase were similar.