Departments of Biology and Plant Sciences, University of California, Riverside, California 92502.
Plant Physiol. 1977 Jun;59(6):1034-8. doi: 10.1104/pp.59.6.1034.
Cotton (Gossypium hirsutum L.) ovules grown in a defined nutrient medium undergo normal morphogenesis, including fiber production. In identical medium lacking boron, ovules callus and accumulate brown substances. Boron deficiency-like symptoms were induced by 6-azauracil and 6-azauridine in ovules growing in boron-sufficient media. Other nucleoside base analogs either reduced or had no effect on over-all growth, but did not cause typical boron-deficient callus growth of cotton ovules. Orotic acid and uracil countered the effects of 6-azauracil. Actinomycin D, fluorodeoxyuridine, and ethidium bromide reduced not only fiber production on ovules growing in boron-sufficient media but also callusing of ovules in boron-deficient media.Similarities between symptoms of boron deficiency and 6-azauracil injury, and the ability of uracil to suppress both, suggest that boron deficiency symptoms are related to reduced activity in the pyrimidine biosynthetic pathway. Growth inhibition by most nucleoside base analogs tested, actinomycin D, fluorodeoxyuridine, and ethidium bromide, as compared to callusing brought on by boron deficiency and 6-azauracil, indicates that boron deficiency symptoms are not related to a reduction in nucleic acid biosynthesis. Based on this information, a discussion of the possibility that boron deficiency causes reduced synthesis of UDP-glucose is presented.
在定义明确的营养培养基中生长的棉花胚珠经历正常的形态发生，包括纤维生产。在缺乏硼的相同培养基中，胚珠会产生愈伤组织并积累棕色物质。在硼充足的培养基中生长的胚珠中，6-氮杂尿嘧啶和 6-氮杂尿苷会引起类似于硼缺乏的症状。其他核苷碱基类似物要么减少要么对整体生长没有影响，但不会导致棉花胚珠典型的硼缺乏愈伤组织生长。乳清酸和尿嘧啶对抗 6-氮杂尿嘧啶的作用。放线菌素 D、氟脱氧尿苷和溴化乙锭不仅减少了在硼充足培养基中生长的胚珠上的纤维生成，而且减少了在硼缺乏培养基中胚珠的愈伤组织生长。硼缺乏症和 6-氮杂尿嘧啶损伤的症状之间的相似性，以及尿嘧啶抑制两者的能力，表明硼缺乏症与嘧啶生物合成途径活性降低有关。与硼缺乏和 6-氮杂尿嘧啶引起的愈伤组织相比，大多数核苷碱基类似物、放线菌素 D、氟脱氧尿苷和溴化乙锭的生长抑制作用表明，硼缺乏症的症状与核酸生物合成的减少无关。基于这些信息，讨论了硼缺乏导致 UDP-葡萄糖合成减少的可能性。
