To most people"mathematies"is synonymous(同义词的,类语的) with "figuring". Actually this idea is far from the truth. Aside from the many geometrical qnes-tions which are not at all concerned with a...To most people"mathematies"is synonymous(同义词的,类语的) with "figuring". Actually this idea is far from the truth. Aside from the many geometrical qnes-tions which are not at all concerned with adding, sub-tracting. multiplying. and dividing, there are problems of quite different sorts whose solution are obtained by the direct exercise of the powers of reasoning. without the intervention(插进,介入) of formulas and computations. For mathematics is applied logic in its simplest and purest form. To demonstratc our c...展开更多
报道了一种新发现的小麦雄性不育系(MSTE型雄性不育,分蘖穗不育male sterility in till-ers ears)。该不育系主茎穗可部分结实,结实率10%～40%,但分蘖穗不育不实。该不育系与普通小麦品种杂交,绝大多数后代育性得到恢复,恢复度达80%以...报道了一种新发现的小麦雄性不育系(MSTE型雄性不育,分蘖穗不育male sterility in till-ers ears)。该不育系主茎穗可部分结实,结实率10%～40%,但分蘖穗不育不实。该不育系与普通小麦品种杂交,绝大多数后代育性得到恢复,恢复度达80%以上。不育系的主茎穗结实籽粒保持其不育特性。晚秋到早春分期播种不改变不育系育性特点。细胞学观察发现,该不育系减数分裂中有较高频率的花粉母细胞出现单价体、落后、染色体桥、微核等结构和数目变异现象,说明该不育系的不育性与染色体的变异有关,与光温反应关系不密切。展开更多
文摘To most people"mathematies"is synonymous(同义词的,类语的) with "figuring". Actually this idea is far from the truth. Aside from the many geometrical qnes-tions which are not at all concerned with adding, sub-tracting. multiplying. and dividing, there are problems of quite different sorts whose solution are obtained by the direct exercise of the powers of reasoning. without the intervention(插进,介入) of formulas and computations. For mathematics is applied logic in its simplest and purest form. To demonstratc our c...
文摘报道了一种新发现的小麦雄性不育系(MSTE型雄性不育,分蘖穗不育male sterility in till-ers ears)。该不育系主茎穗可部分结实,结实率10%～40%,但分蘖穗不育不实。该不育系与普通小麦品种杂交,绝大多数后代育性得到恢复,恢复度达80%以上。不育系的主茎穗结实籽粒保持其不育特性。晚秋到早春分期播种不改变不育系育性特点。细胞学观察发现,该不育系减数分裂中有较高频率的花粉母细胞出现单价体、落后、染色体桥、微核等结构和数目变异现象,说明该不育系的不育性与染色体的变异有关,与光温反应关系不密切。
