【作者】 于涛；

【导师】 姚雅琴；

【作者基本信息】 西北农林科技大学 ， 植物学， 2011， 硕士

【摘要】 玉米是耗水量大的作物,研究水分亏缺下玉米生理、形态的变化以及对胁迫的响应能够为实际的农业生产提供必要的理论依据。本试验通过调亏灌溉的方法对盆栽玉米设定不同控水梯度处理[田间最大持水量的75%～85%（对照）、65%～75%（轻度）、55%～65%（中度）、45%～55%（重度）],运用生理学实验技术结合常规染色、荧光染色、显微形态观察、细胞化学定位等手段,从生理学、形态学、解剖学和细胞化学角度,研究了苗期、拔节期玉米根和叶组织的形态、解剖结构和H₂O₂积累变化对水分亏缺的响应。研究结果如下:（1）水分亏缺对根毛生长的影响:苗期和拔节期,水分亏缺下玉米根毛直径均变细,根毛长度和密度增加,根尖到根毛区距离缩短,其中重度处理的根毛密度最大,根尖端到根毛区的距离最短。复水后各处理组与复水前相比,根毛直径、长度、密度、根尖到根毛区距离无明显变化。（2）水分亏缺对玉米根毛区解剖结构的影响:玉米苗期、拔节期根毛区皮层薄壁细胞随着水分亏缺程度的加剧,细胞体积缩小变形,排列不规则,导致皮层厚度逐渐变薄。苗期轻度水分亏缺促进玉米内皮层细胞径向壁木质化、栓质化加厚,细胞变形不明显,而中度、重度处理的内皮层细胞壁木质化、栓质化程度低,内皮层细胞变形明显;拔节期内皮层细胞壁发育为成熟的“马蹄形”加厚,轻度、中度水分亏缺促进内皮层细胞径向壁、内切向壁木质化、栓质化加厚,细胞变形不明显,只有重度处理内皮层细胞变形。复水后,内皮层细胞继续发育进入后期,细胞壁加厚程度增加。（3）水分亏缺对玉米叶片气孔的影响:水分亏缺程度与气孔密度呈正相关,与气孔开度呈负相关,重度处理气孔开度最小。复水后,轻度处理组气孔开度恢复到正常水平,中度、重度气孔开度得到一定程度的恢复。（4）水分亏缺对根和叶片中H₂O₂含量的影响:随着水分亏缺程度的加剧,根和叶片中H₂O₂含量均升高,在重度处理时达到最大。复水后,轻度水分处理的H₂O₂含量下降到接近正常对照水平。中度、重度处理的H₂O₂含量高于正常对照,但差异不显著。（5）水分亏缺对根中H₂O₂分布和积累的影响:荧光标记表明水分亏缺处理下,玉米根尖端是产生H₂O₂的主要部位。随着水分亏缺程度的加剧,H₂O₂的分布区域从根冠向分生区和伸长区逐渐延伸,H₂O₂的含量也逐渐增多。CeCl3标记显示H₂O₂主要分布于细胞膜和细胞间隙,拔节期处理组H₂O₂的积累量高于苗期。中度、重度处理组除了在细胞膜和细胞间隙存在大量的H₂O₂外,液泡膜、线粒体膜上也出现H₂O₂的积累,其中重度处理组细胞出现线粒体肿胀、嵴减少的现象。复水后,苗期和拔节期处理组根尖细胞中的H₂O₂不同程度的减少,但中度、重度处理的细胞膜、细胞间隙仍存在少量H₂O₂积累。综上所述,玉米通过促进根毛发育,改变皮层厚度,增加内皮层木质化、栓质化程度,调节气孔开关,增加根尖H₂O₂积累来响应水分亏缺产生的胁迫。更多还原

【Abstract】 Maize is one of the largest water consumption crops, researching water deficit on the change of physiology and morphology and response to stress can provide essential theoretical foundation for the practical agriculture production. In a pot experiment with water treatments: 75%-85% of field capacity （control）, 65%-75% of field capacity （light deficit）, 55%-65% of field capacity （moderate deficit）, and 45%-55% of field capacity （severe deficit）. To research water deficit and rewatering on the change of morphology, anatomical structure and H₂O₂ accumulation in root and leave of maize, which is in seelding and jointing stage, with physiology experiment technology, green and the counterstain safranin stain , fluorescent dyes stain, SEM and cell chemistry labeling. The results were as follows:The effect of water deficit on root hair of maize:After water deficit treatment in seedling, maize root hair became thin, root hair density increased, distance from root point to root hair shortened, which was most denser in root hair and shortest distance from root point to root hair with severe treatment. Rewatering had no significant effect on root hair density and distance from root tip to root hair of maize root hair corn root has no evident change.It showed that decrease of codex parenchyma cells area and deformation shape with irregular arrangment resulted in width of codex in root hair zone of maize seedling and jointing getting thinner. With increasing water deficit, the endodermis in root hair zone of maize seedling decreased and deformated obviously, Comparatively, the endodermis of maize jointing changed unconspicuously, caused by mature casparian band enhenced mechanical strength of endodermis. Fluorescence observations showed that axial walls of endodermis thickened on seedling stage with light deficit. Both axial and inner tangential walls of casparian band of endodermis thickened more obviously on jointing stage with light and moderate deficit. Because of it developed into late growth, endodermis cell wall got more thickened after rewatering.The effect of water deficit on the stomata of maize: water deficit level is correlated positively with the density of stomata, and negative correlation with Stomata aperture, which get the highest level reduce in stomata aperture with severe disposal. After rewatering, the level of Stomata aperture were closed to control, the Stomata aperture of moderate deficit and severe deficit treatment recovered resume to a certain extent.The effect of water deficit on the H₂O₂ contents of roots and leaves: As the levels of water deficit aggravate, the H₂O₂ contents of roots and leaves rised up, which got to the highest content in the severe treatment. After rewatering, the H₂O₂ content in moderate deficit declines to the normal control. The H₂O₂ contents of moderate deficit and severe deficit was higher than the control, but the difference was not remarkable.The effect of water deficit on the distribution and accumulation of H₂O₂ in root: The result of water deficit on fluorescent stain showed maize root tip produce the most of H₂O₂. As the water deficit extend is aggravating, the accumulation of H₂O₂ increased and extented from root tip to meiosis zone. The result of CeCl3 labeling indicates that H₂O₂ mainly distributes on the cell membrane and the intercellular space of cells. The H₂O₂ accumulation of the treatments in jointing stage was higher than that in seedling period. In the moderate and severe deficit, the H₂O₂ accumulation was not only on the cell membrane and the intercellular space, but also on the tonoplast and mitochondria. In addition, the cell of root tip appears mitochondria swell and mitochondrialcristae reduce in the severe deficit. After rewatering, H₂O₂ have different degree of reduced in the treatments of jointing and seedling stage, there are still a few accumulation on the cell membrane and the intercellula space the moderate and severe.In sum, in order to influence the force of water deficit, maize promotes the root hair growth, changes the cortex thickness, increases the level of lignifications qualitative of endodermis., adjust Stomata aperture, increases the accumulation of H₂O₂ in root tip.更多还原