为探索低桩机割再生稻高产途径,研究了水稻品种佳辐占再生分蘖节根的萌发特性.结果表明:头季低桩机割后再生季成穗分蘖为倒4、倒5节分蘖及其子蘖; 倒4、倒5节分蘖有4个发根节,子蘖有3个发根节,每节萌发5～8条节根.各节节根萌发有恒定叶龄期:当第n节叶片开始伸长时,第n-3节节根开始萌发(节根原基突破茎秆表皮); 当第n节叶片刚抽出时(该叶伸长近半),第n-3节少数节根显著伸长; 当第n节叶片抽出70%时(该叶定长),第n-3节节根萌发数稳定.倒4、倒5节分蘖在头季机割后约10 d,子蘖在头季机割后约20 d,开始从前出叶节萌发节根,至孕穗初始期前后最上一节节根结束萌发,抽穗后不久全部侧根结束萌发.上述结果可为调控再生稻根系发育提供科学依据.
To improve grain yield of ratoon rice harvested by low stubble machine-cut,germination of nodal roots of ratooning tillers of ratoon rice cultivar Jiafuzhan was studied.The productive primary and secondary tillers were found to be located at the fourth and fifth nodes from the top of theratoon rice plant by low stubble machine-cut in main crop.The primary tillers had 4 rooting nodes,while the secondary tillers had 3 rooting nodes,and there were 5-8 roots formed on each node.The root germination was closely correlated with the leaf age:the nodal root primordium on rooting node n-3 began to germinate(i.e.the nodal root primordium broke through stem epidermis)when the leaf n began to elongate,and it elongated significantly as the leaf n reached half of its maximum length,while the number of the roots did not change once the leaf n stopped growing.In the ratoon crop,the primary and the secondary tillers started to germinate roots at 10 d and 20 d after harvest in the main crop,respectively.These roots were found on the prophyll nodes and terminated on the uppermost nodes before and after the beginning of booting stage.Germination of the lateral roots ended soon after the emergence of headings.The observations may provide the basic information on the root development of ratoon rice Jiafuzhan.
