禾本科植物基因组大小与种子特性的相关性分析

Correlation Analysis between Genome Size and Seed Characteristics in Poaceae Plants

在检索植物C值数据库和种子数据信息库的基础上,对禾本科282种植物的基因组参数(倍性、染色体数、C值、GS值和平均每条染色体DNA含量)和种子特性(千粒重、含油量和蛋白含量)进行了统计分析。分析结果表明,禾本科植物C值在0.35～19.7 pg,大多位于1.6～3.2 pg之间,呈偏正态分布,种子千粒重在0.05～252 g,绝大多数位于0.05～20.0 g,呈偏态分布,二者平均值分别为4.14 pg和7.1 g。随着染色体倍性增加,C值在二倍体到八倍体之间显著增加,而GS值和平均每染色体DNA含量在二倍体到六倍体之间显著下降(p<0.05)。雀麦属和羊茅属随着倍性增加,C值显著增加,表现与禾本科相似的变化规律,GS值下降却不明显。相关性分析表明,禾本科植物C值与倍性、染色体数、GS值及平均每条染色体DNA含量均呈极显著正相关(p<0.01),与种子千粒重无相关性。GS值与染色体数、倍性呈极显著负相关,而与千粒重呈极显著正相关。C值与种子含油量呈显著负相关,但与种子蛋白含量之间无相关性。以上结果表明,禾本科植物在系统演化和进化过程中,主要通过倍性和染色体的增加来增大C值,可能通过某种删除或丢失机制来降低GS值,从而保持较高的适应环境能力和进化速率。

The relationship between Characteristics of genome size （ploidy, chromosome number, C-value and GS ） and seed （1000-seed weight, oil content and protein content）, which were searched from Plant C-value Da- tabase and Seed Mass Information Database, was analyzed by ANOVA and regression model for 282 species in Poaceae. The results showed that the C-value and 1000-seed weight changed 05 to 252 g, and the means were 4.14 pg and 7.1 g, respectively. With the from 0.35 to 19..7 pg and from 0. ploidy increasing, the C-values in- creased significantly from diploid to 0ctoploid, but the GS and mean DNA content of each chromosome decreased significantly from diploid to hexaploid （p 〈 0. 05 ）. The C-value of Bromus and Festuca showed similar change as Poaceae, but GS did not decrease Significantly. Linear correlation analysis showed that there were ~significantly positive correlations between C-value and ploidy, number of chromosome, GS and mean DNA content of each chromosome, but there were significantly negative correlations between GS and number of chromosome and pl0idy （p 〈0, 01 ）. Regression analysis showed that there was significantly positive correlation between GS and 1000- seed weight （p 〈 0.01 ）, but there was almost no correlation between C-value and 1000-seed weight. There was significantly negative correlation between C-value and oil content of seeds, but no correlation between C-value and protein content. There was higher species in Poaceae increased their C-values primarily by ploidy doubling in the phylogeny and evolution history, but at the same time, reducing GS and mean DNA content. This study will give the C-value was stopped to increase infinitely through some reference to study the relationship between ge-nome size evolution and plant phylogeny.