Developmental changes occur in maize (Zea mays L.) as it transitions from juvenile stages to the mature plant. Changes also occur as newly formed cells mature into adult cells. Maize leaf blades including the midribs ...Developmental changes occur in maize (Zea mays L.) as it transitions from juvenile stages to the mature plant. Changes also occur as newly formed cells mature into adult cells. Maize leaf blades including the midribs and sheaths undergo cell wall changes as cells transition to fully mature cell types. As is common in grasses during cell wall maturation, the lignin in the plant tissue is acylated with p-coumarates (pCA). This work characterizes cell walls in maize that make up leaf blade, leaf midrib, and sheath tissues corresponding to tissue development. Maize plants grown in the greenhouse were harvested;leaf, leaf midrib, and sheath tissues from nodes 9 through 14 tissues were analyzed for cell wall composition. Cell wall carbohydrates varied with the type of maize tissue, but there was little change within a tissue type among the different nodes. Lignin concentrations were lowest in the leaf blade (70 - 88 g·kg-1 CW) followed by the sheath (123 - 140 g·kg-1 CW) and highest in the midrib (140 - 168 g·kg-1 CW). Incorporation of pCA into cell walls paralleled the lignification. Ferulates (FA) remained relatively constant as a proportion of the cell wall (3.1 - 6.4 g·kg-1 CW) across nodes and across all tissue types. The range of FA was 3.8 vs 5.7 g·kg-1 CW averaged over all nodes with leaf blades being the lowest. Lignin composition did not change significantly with cell wall maturation within a given tissue type. The aerial portions of maize plants excluding the stem showed little difference in cell wall composition along the different nodes. Higher levels of ferulates were found in the sheath and leaf midrib compared to the leaf blade tissues. Leaf midribs from the upper nodes of the plant contained the highest levels of lignin. Perhaps a reflection of the function to keep leaves extended and in an upward angle to help maximize photosynthetic capacity.展开更多
The cross-linked nature of plant cell walls provides structural integrity for continued growth and development, but limits degradation and utilization by ruminants. In grasses a major cross-linking component is feruli...The cross-linked nature of plant cell walls provides structural integrity for continued growth and development, but limits degradation and utilization by ruminants. In grasses a major cross-linking component is ferulic acid that is incorporated into cell walls as an ester linked residue on arabinoxylans. Ferulates can become coupled to each other and to lignin forming a highly cross-linked matrix of carbohydrates and lignin. Seedling ferulate ester mutants (sfe) were produced in maize using the transposon system and evaluated in feeding trials. The work described here was undertaken to characterize changes in the ferulate cross-linked nature as well as other components of the corn cell wall matrix in leaf, sheath and stem tissues. Total ferulates decreased modestly due to the mutation and were more apparent in leaf tissue (16% - 18%) compared to sheath (+5 to?-6% change) and stem (8% - 9% decrease). The most significant changes were in the ether linked ferulates to lignin, both monomer and dehydrodiferulates (14% to 38% decrease). Other characteristics of the cell wall (lignin, neutral sugar composition) also showed modest changes. The change in total ferulates was modest, but led to improved animal performance. These findings suggest that relatively small changes can have a significant impact upon how well plant materials can be broken down and utilized by ruminants such as dairy cows.展开更多
文摘Developmental changes occur in maize (Zea mays L.) as it transitions from juvenile stages to the mature plant. Changes also occur as newly formed cells mature into adult cells. Maize leaf blades including the midribs and sheaths undergo cell wall changes as cells transition to fully mature cell types. As is common in grasses during cell wall maturation, the lignin in the plant tissue is acylated with p-coumarates (pCA). This work characterizes cell walls in maize that make up leaf blade, leaf midrib, and sheath tissues corresponding to tissue development. Maize plants grown in the greenhouse were harvested;leaf, leaf midrib, and sheath tissues from nodes 9 through 14 tissues were analyzed for cell wall composition. Cell wall carbohydrates varied with the type of maize tissue, but there was little change within a tissue type among the different nodes. Lignin concentrations were lowest in the leaf blade (70 - 88 g·kg-1 CW) followed by the sheath (123 - 140 g·kg-1 CW) and highest in the midrib (140 - 168 g·kg-1 CW). Incorporation of pCA into cell walls paralleled the lignification. Ferulates (FA) remained relatively constant as a proportion of the cell wall (3.1 - 6.4 g·kg-1 CW) across nodes and across all tissue types. The range of FA was 3.8 vs 5.7 g·kg-1 CW averaged over all nodes with leaf blades being the lowest. Lignin composition did not change significantly with cell wall maturation within a given tissue type. The aerial portions of maize plants excluding the stem showed little difference in cell wall composition along the different nodes. Higher levels of ferulates were found in the sheath and leaf midrib compared to the leaf blade tissues. Leaf midribs from the upper nodes of the plant contained the highest levels of lignin. Perhaps a reflection of the function to keep leaves extended and in an upward angle to help maximize photosynthetic capacity.
文摘The cross-linked nature of plant cell walls provides structural integrity for continued growth and development, but limits degradation and utilization by ruminants. In grasses a major cross-linking component is ferulic acid that is incorporated into cell walls as an ester linked residue on arabinoxylans. Ferulates can become coupled to each other and to lignin forming a highly cross-linked matrix of carbohydrates and lignin. Seedling ferulate ester mutants (sfe) were produced in maize using the transposon system and evaluated in feeding trials. The work described here was undertaken to characterize changes in the ferulate cross-linked nature as well as other components of the corn cell wall matrix in leaf, sheath and stem tissues. Total ferulates decreased modestly due to the mutation and were more apparent in leaf tissue (16% - 18%) compared to sheath (+5 to?-6% change) and stem (8% - 9% decrease). The most significant changes were in the ether linked ferulates to lignin, both monomer and dehydrodiferulates (14% to 38% decrease). Other characteristics of the cell wall (lignin, neutral sugar composition) also showed modest changes. The change in total ferulates was modest, but led to improved animal performance. These findings suggest that relatively small changes can have a significant impact upon how well plant materials can be broken down and utilized by ruminants such as dairy cows.
