【作者】 王俊丽；

【导师】 李杨瑞； 林鉴钊；

【作者基本信息】 广西大学 ， 作物栽培学与耕作学， 2003， 硕士

【摘要】 观察甘蔗茎尖纵切面，初生增粗分生组织发生于茎尖顶端的原生分生组织，与原表皮、基本分生组织和原形成层束一起构成茎尖的初生分生组织。 初生增粗分生组织位于茎尖伸长区叶原基或幼叶的基部，细胞主要进行平周分裂，垂周向排列。从第3～5幼叶基部，初生增粗分生组织细胞层数逐渐增加，细胞分裂能力强，分化程度低；第6～7幼叶初生增粗分生组织已明显分化出较多薄壁细胞和原形成层束；大约从第8幼叶开始，初生增粗分生组织的细胞层数向基逐渐减少，分裂势减弱，其细胞逐渐分化成薄壁细胞和原形成层束。众多细胞数量和体积的增加，使蔗茎增粗。 初生增粗分生组织分化形成的原形成层束在茎中占绝大部分，其中导管、原生韧皮部筛管的分化过程以及一些细胞的自然衰退死亡现象与细胞程序性死亡过程相似。 6个茎径不同的甘蔗品种即粤糖86／368(YT86／368)、粤糖91／976(YT91／976)、桂糖11(GT11)、新台糖16(ROC16)、CP80-1827、农林8号(NL8)初生增粗分生组织的细胞分裂指数都大于顶端分生组织的，而且二者细胞分裂存在明显同步性，并且细胞分裂指数与蔗茎有一定正相关关系。 通过对茎径不同的3个甘蔗品种YT86／368、GT11、NL8的研究表明：各品种初生增粗分生组织的面积、原形成层束一维管束的密度和数量均是大茎品种YT86／368＞中茎品种GT11＞小茎品种NL8，与茎粗成一定正相关关系。每个品种的初生增粗分生组织的面积是第5幼叶基部＞第4幼叶基部＞第3幼叶基部；第6～11幼叶所对茎中的原形成层束一维管束的密度和数量均表现为：外层＞中层＞内层。 一定浓度的 IAA 禾 6－BA组合处理对两个品种 GT92／126、GT96／24茎尖导管的分化有促进作用，还有使导管径向扩大及薄壁细胞横向加宽的作用；据激素浓度的配比不同，其促长的效果也不一样；不同激素组合对原形成层束的分化均有抑制作用。更多还原

【Abstract】 Observed from the longitudinal section in shoot apex of sugarcane, the primary thicking meristem (PTM) originated from promeristem of the shoot apex, and the primary meristem consisted of protodem, ground meristem, primary thicking meristem and procambial bundles.The PTM usually existed in the bases of leaf primordium and young leaves in elongation zone of the shoot apex, its cells divided predominantly in periclinal planes and were arranged perpendicular to the stem surface (anticlinal). From the base of the 3rd young leaf to that of the 5th one, there was a increasing tendency in cell files of the PTM, and the cells of the PTM rapidly divided and less differentiated. From the base of the 6th to 7th leaf, more parenchymas and procambia bundles developed from the PTM. Approximately from the base of 8th leaf, there was a basipetally decreasing tendency in cell files of the PTM, and its cells slowly divided, most of the PTM cells differentiated into parenchynas and procambia bundles until the mature zone. The cells increased in quantity and enlarged in volume made the stem diameter thicker.Most of the procambium bundles came from the PTM. The differentiating process of xylem, protophloem sieve element and some cells’ natural degeneration or death were similar to the programmed cell death.The cell division indexes of PTM in six varieties(YT86/368, YT91/976, GT11, ROC16, CP80-1827, NL8) with different stem diameter were higher than those of the apical meristem, but both of them showed similar curves.In addition, the cell division indexes were positively correlated with the stem diameter.Studies on three sugarcane varieties(YT86/368,GT11,NL8)showed that the total areas of PTM, the density and the quantity of procambial bundles-vascular bundles were positively correlated with the stem diameter, those of YT86/368>those of GT11 >those of NL8. The PTM. area of the fifth leaf base> that of the fourth one > that of the third one, thedensity and the quantity of procambial bundles-vascular bundles in the stems coincided with the 6th-11th leaves were that : the outer layer>the middle one > the inner one in each variety.Treatments of combinations of densities of IAA/6-BA showed stimulating effects on the differentiation of vessels, and made the diameters of vessels enlarged and the parenchyma cells traversely wider in GT92/126 and GT96/24; the different hormone density ratios had different stimulating effects on them; The different hormone combinations showed the inhibitions on the differentiations of procambial bundles in the two varieties.更多还原