Abstract: Three mutated rice populations, derived from dried seeds of M₁ materials (ca 13.5% moisture) treated with 300 Gy of 60Co gamma rays at 0.8 Gy/min, or 250 Gy followed by 2-hour treatment of germinating seeds in NaN₃ solution (1×10 ^-3 mol/L), were screened for high inorganic phosphorus (HIP) seeds. The frequency and transmission mode of HIP seeds from M₂ to M₅ were investigated. Using a 96-well V-type plate, the inorganic P (iP) content of 8 individual seeds from each plant was qualitatively tested using five standard P (KH₂PO₄) solutions, equal to seed P concentrations of 0.00, 0.15, 0.46, 0.93 and 1.39 mg/g. Seed showed higher iP than 0.46 mg/g was chosen as a HIP seed, and M₂ plant with at least 1 HIP M₃ seed was designated as a tentative HIP plant, and the same for M₃ and higher generations. Less than expected number of HIP M₃ plant lines (M_2:3) were identified from HIP M₂ plants. However, most HIP M₃ lines yielded HIP M₄ progenies. Based on the number of HIP plant lines in M₃ and M₄, it was estimated that HIP mutation frequency was around 0.1% in rice. Two bred-true HIP mutant lines, one from indica rice Xieqingzao B, named HIPi1, the other from japonica rice Xiushui 110, named HIPj1, were developed. Analysis of the brown rice showed that, compared with its parent, the phytic acid P of HIPi1 decreased about 35% and iP content increased as high as 3.5 times, while total P remained almost unchanged. A protocol was proposed for HIP mutant inducing, screening and breeding for rice based on the finding.

Key words: rice, phytic acid, inorganic phosphorus, mutation, breeding

摘要： 摘要: 以3份水稻诱变群体为材料，详细研究了M2~M5代高无机磷(high inorganic phosphorus, HIP)种子出现的频率和传递特征。这些材料来自含水量约13.5%的水稻干种子用300 Gy 60Co伽玛射线 （剂量率0.8 Gy/min）处理，或经250 Gy 处理后再对其萌动种子用1×10-3 mol/L的 NaN3 溶液常温下处理2 h所得M1的后代。在96 孔V型酶标板上， 设置5个用KH2PO4配制的标准P溶液，浓度相当于种子磷含量0.00、 0.15、 0.46、 0.93和1.39 mg/g。分析时每个单株分析8粒种子，无机P（iP）高于0.46 mg/g的籽粒称为高无机磷（HIP）种子，出现至少1粒HIP M3种子的M2单株称为HIP M2单株，M3及高代由此类推。研究发现，从HIP M2单株衍生的M3株系中，HIP株系数要少于HIP M2单株数。但是多数M3 HIP株系后代都获得了更高代的HIP株系。根据M3和M4 HIP株系数推算，水稻HIP突变的实际频率可达0.1%左右。已从籼稻协青早B和粳稻秀水110中各选得一个HIP纯合突变系HIPi1和HIPj1。对HIPi1糙米中各种磷素定量分析表明，突变体中植酸磷含量较对照下降约35%，无机磷含量上升约3.5倍，而总磷基本不变。最后提出了水稻HIP突变体诱发、筛选和选择的基本方法和程序。

关键词: 水稻, 植酸, 无机磷, 突变体