不同铵硝比对生菜叶绿素合成的影响

Effects of different nitrogen ratios on chlorophyll synthesis of lettuce seedlings

【目的】为了找到适合生菜生长的铵态氮和硝态氮比例(铵硝比)。【方法】以‘北散生1号’生菜为试验材料,采用水培方法,设置全铵态氮处理,7525,5050,2575和全硝态氮处理5个,测定不同铵硝配比下生菜叶绿素及叶绿素合成前体的含量。【结果】在铵硝比为2575时的生长状况最佳,地上部与地下部的干鲜质量均最大,且处理间有显著性差异,铵硝比为7525时生菜与铵硝比为5050时的长势相对较差;叶绿素总量与叶绿素a/b均为完全硝态氮处理最高,完全铵态氮处理最低,且两个处理间有显著性差异;在铵硝比为2575时,叶绿素及5–氨基酮戊酸(ALA)、胆色素原(PBG)、尿卟啉原Ⅲ(Urogen Ⅲ)、原卟啉Ⅸ(Proto Ⅸ)、原叶绿素酸(Pchl)含量最高,铵硝比为7525时含量最少;铵硝比为2575时,尿卟啉原Ⅲ(Urogen Ⅲ)含量显著高于其他处理,其他处理间差异不显著。叶绿素合成前体的关键酶,δ-氨基酮戊酸脱水酶(ALAD)、胆色素原脱氨酶(PBGD)、尿卟啉原合成酶(UROS)、原卟啉原氧化酶(PPO)均在铵硝比为2575时最高。【结论】铵硝比为2575时生菜植株形态较好,叶绿素含量与叶绿素合成前体含量相对较高,较适宜生菜生长。

A suitable ratio of ammonium nitrogen(NH4^+-N)to nitrate nitrogen(NO3--N)for lettuce growth was investigated.5 ratios of ammonium and nitrate(total ammonia nitrogen,7525,5050,2575 and total nitrate)were set by hydroponic method for'Beisansheng No.1'lettuce.The effects of different ammonium nitrate ratios on the content of chlorophyll and chlorophyll synthesis were observed.The ratio of ammonium to nitrate 2575 showed the best growing,and the dry weights of the shoot and root were the most.Total chlorophyll and chlorophyll a/b were treated highest with complete nitrate nitrogen,and treated with complete ammonia nitrogen was lowest,and there was significant difference between the two difference.When the ammonium-nitrate ratio is 25∶75,chlorophyll and 5-aminoketovaleric acid(ALA),bilirubinogen(PBG),uroporphyrinogen Ⅲ(Urogen Ⅲ),protoporphyrin Ⅸ(Proto Ⅸ),and prochlorophyllin(Pchl)content is the highest,the content is lowest when the ammonium-nitrate ratio is 75∶25.The key enzymes for chlorophyll synthesis precursors,δ-aminolevulinate dehydratase(ALAD),porphobilinogen deaminase(PBGD),uroporphyrinogen synthase(UROS),protoporphyrinogen oxidase(PPO)were as well.When The contentsof chlorophyll and chlorophyll synthesis precursor were promoted at the ratio of ammonium to nitrate 2575,which gave the suitable growth conditions for lettuce.