FORAGE QUALITY VARIATION AMONG MAIZE INBREDS - RELATIONSHIPS OF CELL-WALL COMPOSITION AND IN-VITRO DEGRADABILITY FOR STEM INTERNODES
FORAGE QUALITY VARIATION AMONG MAIZE INBREDS - RELATIONSHIPS OF CELL-WALL COMPOSITION AND IN-VITRO DEGRADABILITY FOR STEM INTERNODES
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DOI：
10.1002/jsfa.2740660308
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发表时间：
1994-11-01
影响因子：
4.1
通讯作者：
BUXTON, DR
中科院分区：
文献类型：
--
作者：
JUNG, HJG;BUXTON, DR
对45个玉米自交系L的细胞壁浓度、组成和降解率的遗传变异以及细胞壁成分与多糖降解率的关系进行了研究。对2年吐丝时采集的下部茎节间样品进行了细胞壁中性糖、糖醛酸、Klason木质素、酯键和醚键酚酸的测定。用24个96h的体外瘤胃发酵液分别测定了快速降解和潜在降解的细胞壁多糖组分。对细胞壁组成的所有指标以及对快速和潜在可降解的细胞壁多糖成分的许多估计都发现了遗传变异(P<；0.05)。自交系大多数性状的变异幅度在50%-300%之间。研究中包括的三个棕色中脉突变体自交系的木质素含量并不是该自交系中最低的，也不是该自交系群体中细胞壁降解率最高的。生长年份(环境)影响(P<；0.05)细胞壁性状，尽管两年采样时的生殖生理成熟度相似。在快速和潜在可降解组分中，细胞壁多糖组分的降解率相关(P<；0.05)，但除糖醛酸外，细胞壁组分的降解率和降解率不相关(P>；0.05)。主成分多元回归模型(R(2)=0.41，P<；0.05)表明，细胞壁木质化和壁上聚合物被酚酸和糖醛酸取代呈负相关，果胶类物质与多糖的快速降解呈正相关。这种多元回归分析可以解释细胞壁多糖潜在降解率的极小变异(R(2)=0.15，P<；0.05)。当前的玉米自交系在干细胞壁品质性状上存在很大程度的遗传变异，这应该有助于玉米作为饲料作物进行改良。然而，由于细胞壁组织中复杂的基质相互作用，没有单一的细胞壁成分或简单的组合可以准确地预测玉米细胞壁的降解率。
Forty-five inbred maize (Zea mays L) lines were evaluated for genetic variation in stem cell-wall concentration, composition and degradability, and for relationships among cell-wall components and polysaccharide degradability. Cell-wall neutral sugars, uronic acids, Klason lignin, and ester- and ether-linked phenolic acids were measured on lower stem internode samples collected at the time of silking in 2 years. Twenty-four and 96 h in-vitro ruminal fermentations were used to determine the rapidly and potentially degradable cell-wall polysaccharide fractions, respectively. Genetic variation (P < 0.05) was found for all measures of cell-wall composition and many estimates of rapidly and potentially degradable cell-wall polysaccharide components. Inbred line means varied by 50-300% for most traits. Three brown midrib mutant inbred lines included in the study were not the lowest in lignin content nor did they exhibit the greatest cell-wail degradabilities in this population of inbred maize. Year of growth (environment) influenced (P < 0.05) cell-wall traits even though reproductive physiological maturity at sampling was similar in both years. Degradability of the cell-wall polysaccharide components were intercorrelated (P < 0.05) within the rapidly and potentially degradable fractions, but rate and extent of degradation of the cell-wall components were not correlated (P > 0.05), except for uronic acids. A multiple regression model of principal components (R(2) = 0.41, P < 0.05) indicated that cell-wall lignification and substitution of wall polymers with phenolic and uronic acids were negatively associated, and pectic substances were positively related with rapid polysaccharide degradation. Very little of the variation (R(2) = 0.15, P < 0.05) in potential cell-wall polysaccharide degradation could be explained by this multiple regression analysis. There is a large degree of genetic variation among current inbred maize lines for stem cell-wall quality traits, which should allow improvement of maize as a forage crop. Because of the complex matrix interactions in cell-wall organization, however, no single cell-wall component, or simple combination, can accurately predict degradability of maize cell walls.