杂交稻后期叶片早衰特征及其与叶片N含量和根系活力关系初探

A Preliminary Study on Relationship between Leaf Premature Senescence Characteristic and Leaf N Content,Roots Activity in Hybrid Rice during Grain Filling Stage

选用17个不同类型的杂交稻组合,抽穗后进行限水胁迫处理和常规水分管理比较试验,研究叶片衰老特征及其与N含量和根系活力下降的关系。结果表明,不同组合抽穗后高效叶面积、叶绿素含量、叶干重、高效叶片含N量、根系伤流量的下降率存在明显差异。叶绿素下降率与叶片N含量、根系伤流量下降率极显著相关。衰老频度涵盖了灌浆结实期单位时间内高效叶面积、叶干重、叶绿素含量3个指标的下降率,可作为判断早衰发生的量化指标。齐穗后的灌浆前期衰老频度达到50即为早衰开始,衰老频度超过100已经明显早衰,衰老频度超过200则说明早衰较严重。超级稻组合茎鞘贮藏物质输出率高、衰老频度高、结实率低主要与库容量大有关。叶片的早衰受N素水平制约,与根系活力有关。

Seventeen hybrid rice combinations were studied to cence and its relationship with decline rate of leaf N content and root tion and conventional management was conducted after the heading discover the characteristics of leaf senesactivity. The comparison of limited irrigaof rice. The results indicated that the decline rates of leaf area, dry matter, chlorophyll content, N content in high -efficiency leaves and xylem sap of roots were significantly different among 17 hybrid rice combinations. Positive correlation existed between decline rates of chlorophyll and N content in leaves and xylem sap of roots. The senescent frequency contained the decline rate of leaf area, dry matter and chlorophyll content at the early filling phase and thus can be an indicator of premature senescence. When the senescence frequency reached 50, the leaves start premature senescence. When it exceeded 100 ,the leaves were obviously premature senescent. With 200 of the frequency, the leaves were seriously premature senescent. The high transpotion rate of culm and sheath, high senescent frequency and low filled grain rate of super hybrid rice combinations could be related to its big sink potential. The premature senescence of leaves was affected by N supply and root activities.