【作者】 孟剑霞；

【导师】 杨晓玲；

【作者基本信息】 山西农业大学 ， 植物学， 2005， 硕士

【摘要】 玉米是高产的粮食作物,其果穗性状是构成产量高低的主要因素。在玉米育种实践中,我们发现某些玉米自交系的苞叶相对雌穗轴短,使得雌穗上部籽粒无苞叶保护,而被外力损害。我们以短苞叶自志系139号和正常苞叶自交系1号为材料,从不同时期玉米果穗生长发育的形态、解剖、生理方面来研究139号苞叶相对雌穗轴变短的原因。实验结果如下: 从玉米果穗发育形态特征方面:(1)139号苞叶层数明显多于对照1号。(2)139号苞叶长度小于1号。(3)139号每层苞叶面积小于1号,由于其苞叶层数多,故139号总面积大于1号。(4)139号雌穗轴比1号粗而长,且139号籽粒比1号的大而饱满。(5)139号苞叶与雌穗轴干重生长动态变化反映了玉米果穗的生长状况。各个时期139号苞叶和雌穗的干重大于1号的。139号授粉后雌穗轴生长快,而苞叶则生长缓慢。 从玉米果穗发育维管束特性方面:运用照片形象表示了苞叶与雌穗轴的维管束结构。对139号与1号苞叶和雌穗轴维管糸面积、数量等进行比较:139号苞叶单个维管束面积与其韧皮部面积大于1号,但在维管束数量上则少于1号。139号雌穗轴单个维管束面积与其韧皮部面积却小于1号,但在数量上多于1号。 从玉米果穗发育生理研究表明:四个时期中139号苞叶硝酸还原酶活性非常低,对照1号的稍高一些。139号苞叶谷氨酰胺合成酶活性小于1号,且1号的酶活性变化较平缓。139号雌穗轴硝酸还原酶活性变化剧烈,授粉后15天达高峰,明显大于1号。139号雌穗轴谷氨酰胺合成酶活性前三时期始终大于1号,最后一时期二者几乎相等,但1号的酶活性变化平缓。 总之,139号苞叶短而穗轴长的原因主要是:从外部形态上看,苞叶层数多,总面积大,每片苞叶可获得的有机物质相对较少,因而苞叶生长缓慢。从内部维管束结构上看,雌穗轴维管束面积较小,但数量多,有利运输更多的养分进入穗轴与籽粒,使其快速生长,表现出生长速度上与其苞叶的不协调。139号果穗发育内在的生理变化是139号苞叶硝酸还原酶活性和谷氨酰胺合成酶均低于1号,且活性非常小;其雌穗轴的硝酸还原酶活性和谷氨酰胺合成酶活性均高于对照,且有生长高峰出现。更多还原

【Abstract】 Maize(Zea may L.) is a high yield provision crop,and its ear characters are one of the main factors of the different yield. In the practice of maize breeding, In the practice of maize breeding,we found some inbred lines was very good except the shorter husk and longer female cob.The husk can’t protect the female ear and the tip of female ear is open to the air so as to damage by outsideforce. In order to study the reason of the short husk variety in the process of inbred lines breeding in maize from morphological , anatomical, physiological perspective, we measured the ear characteristics in the ear growth process with the short husk variety No. 139and the contrast variety No. 1. The results were as follows:From the morphological characteristrics of the ear growth in maize: (1) The husk numbers of No.139 were evidently more than that of the No.1 .(2) The husk length of No.139 was shorter than one of No.1. (3) The areas per husk of No.139 were smaller than that of No.1.Because the husk numbers of No.139 were more than that of No.1,the overall husk areas were larger than that of No.1. (4) The female cob of No.139 was wider and larger than that of No.1.The kernel of No.139 was larger and astitier than that of No. 1.(5) The husk weights and female cob weights of two inbred lines reflected the ear development in maize.In every period,the husk weigth and female cob weight were larger than that of No.1.After pollination,female cob of No.139 growed rapidly.but the husk growed slowly.We studied the vascular bundle structure of two inbred lines with microscopic photograph of the ear in three periods. The single vascular bundle in the husk in 139 were larger than the contrasts.but the numbers of the vascular bundle of 139 were less than the contrast’s .As for the cob ,the vascular bundle areas of 139 were smaller than No.1’s,but the vasculars bundle number of 139 were larger than that of No.l.The physiological studies on the ear development of maize showed:In the four period of ear growth the husk nitrate reductive activity of No.139 was very lower than that of No.1;the husk glutamine synthetase activity was lower than that of No.1,and the change of glutamine synthetase activity of No.1 was flat;The ear nitrate reductive activity of No.139 moved acutely,and after 15days pollination that of No.139 reached maximum that was higher obviously that of No.l at the same period.The ear glutamine synthetase activity of No.139 always higher than that of No.l in the the three period.In the last period ,the ear glutamine synthetase activity of two inbred lines were almost equal.On the all accounts, the reason of why No. 139 (mealie) has short husk and long female cob mainly is it has many husks and the over all area is large. The nutrition of each husk is less than that of others, so it grows slowly. However, on its vascular bundle structure, although the area of vascular bundle is small, there are many vascular bundles. This is propitious to transport more nutrition to the female cob and kernels, and makes them to grow quickly. This phenomenon is different from the growth of husk. .The husk nitrate reductive activity and glutamine synthetase activity of No.139 was lower than that of No.l,and the activity was very small.The cob nitrate reductive activity and glutamine synthetase activity of No.139 were higher than the contrast,and emergenced the growth maximum.更多还原