介质pH和氮形态对玉米苗期根系发育的影响

在介质pH 4.0和6.0条件下研究铵态氮(NH4 -N)和硝态氮(NO3--N)对玉米苗期根系形态及解剖结构的影响。结果表明:介质pH和氮形态均可对玉米苗期根系形态及解剖结构产生影响;以NH4 -N为惟一氮源时,低pH明显抑制玉米侧根的发生,但对根系伸长的抑制并不明显;以NO3--N为单一氮源时,无论是低pH还是近中性条件,对侧根的发生和根系的伸长影响均不明显;以NH4 -N或NO3--N作为氮源,低pH均有利于中柱成熟,在根中央形成大的导管。

Effects of medium pH and N forms on maize root development at the seedling stage

Solution culture experiments were carried out to study the effects of different pH levels(pH 4.0,6.0) and N sources(NH~ _4-N,NO~-_3-N) on morphological traits and structures of maize roots at seedling stage.Results showed that both medium pH and N forms had influence on morphological traits and structures of maize roots at seedling stage.With the presence of NH~ _4-N the low pH level obviously inhibited lateral root formation,whereas the inhibition of root elongation was slight at the same conditions.When NO~-_3-N was used as the sole source medium pH had less effects on root elongation and lateral root formation.Whether NH~ _4-N or NO~-_3-N as the sole N source low pH stimulated the development of vascular cylinder and large xylem vessels.