Kirk J Jane, Deacon J W
Microbiology Department, School of Agriculture, West Mains Road, Edinburgh, EH9 3JG, UK.
New Phytol. 1986 Sep;104(1):63-75. doi: 10.1111/j.1469-8137.1986.tb00634.x.
Nuclear fluorescence following acridine orange staining was used to assess patterns and rates of death of the root cortex (RCD) in Lolium perenne L., L.×hybridum Hausskn. and Dactylis glomerata L. grown in pathogen-free soil in a glasshouse. The pattern of RCD was as previously described for cereals. The rate of RCD differed significantly between grasses and between cultivates of L. pefenne, but in most instances the cortex was anucleate, except for the innermost cell layer next to the endodermis, in 26 to 27 d old regions of seminal root axes. Root impedance caused by a nylon gauze barrier in soil significantly increased the rate of RCD in one tested cultivar of L. perenne. RCD was more rapid in wheat than in grasses. In 8 d old regions of wheat seminal root axes the cortex contained only 54% of the nuclei initially present. Infection of wheat roots by the take-all fungus, Gaeumannomyces graminis (Sacc.) Arx & Olivier var tritici Walker, caused vascular disruption followed by more rapid RCD than in uninfected roots. Similarly rapid RCD occurred in amputated roots, though in all instances the pattern of RCD was unchanged. The rate of RCD was slower in long than in short lengths of amputated root, perhaps because of remobilization of nutrients from dying cells. Nuclei persisted for at least 10 d in the inner cortex of 2 cm lengths of young roots of wheat, barley and L. perenne buried in soil at 20 °C. The pattern of nuclear deletion from the root pieces was the same as in whole roots, and the rate of RCD was faster in wheat than in barley, as also found for roots attached to plants. All these results demonstrate a consistent pattern of cortical senescence in graminaceous roots and suggest that it is a programmed phenomenon.
采用吖啶橙染色后的细胞核荧光来评估多年生黑麦草、杂种黑麦草和鸭茅在温室无菌土壤中生长时根皮层细胞死亡（RCD）的模式和速率。RCD的模式与先前描述的谷类植物相同。RCD的速率在不同草种之间以及多年生黑麦草的不同品种之间存在显著差异，但在大多数情况下，除了靠近内皮层的最内层细胞层外，在26至27日龄的种子根轴区域，皮层细胞无细胞核。土壤中尼龙纱布屏障造成的根系阻抗显著增加了一个多年生黑麦草测试品种的RCD速率。小麦的RCD比草类更快。在8日龄的小麦种子根轴区域，皮层中最初存在的细胞核仅占54%。全蚀病菌（Gaeumannomyces graminis (Sacc.) Arx & Olivier var tritici Walker）感染小麦根系会导致维管束破坏，随后RCD比未感染的根系更快。同样快速的RCD也发生在切断的根中，尽管在所有情况下RCD的模式都没有改变。切断根的RCD速率在长根中比短根中更慢，这可能是因为死亡细胞中营养物质的再利用。在20℃埋于土壤中的2厘米长的小麦、大麦和多年生黑麦草幼根的内皮层中，细胞核至少持续存在10天。根段细胞核缺失的模式与完整根相同，并且小麦的RCD速率比大麦更快，这在与植株相连的根中也有发现。所有这些结果表明禾本科植物根系皮层衰老具有一致的模式，并表明它是一种程序性现象。
