| 摘要: |
| 为明确缺氮胁迫对谷子幼苗生长发育的影响，以‘冀谷45’为试验材料，采用苗期水培法，以全氮营养液培养(15 mol/L N)为对照(CK)，测定缺氮(0 mol/L N，N0)胁迫下幼苗生物量、根系性状、叶片光合色素含量等生理指标，并进行Pearson相关性分析。结果表明:1)缺氮胁迫下，幼苗已展开的真叶出现叶尖干枯症状；与CK相比，缺氮胁迫谷子幼苗的地上部鲜、干重和苗高均显著下降；但幼苗地下部鲜重、地下部干重、根冠比、总根长、根投影面积、根表面积和平均直径等根系性状指数均显著提高；缺氮胁迫下，谷子幼苗叶片的叶绿素a和b含量分别比CK减少32.3%和34.5%，说明缺氮显著抑制幼苗叶片叶绿素的合成。2)缺氮胁迫幼苗叶片的SOD、POD、CAT酶活性和可溶性蛋白质含量分别比CK降低24.9%、43.1%、33.9%和7.0%；MDA和可溶性总糖含量分别比CK提高46.2%和92.5%。3)相关性分析表明，缺氮胁迫下，可溶性总糖含量与幼苗地下部干、鲜重均呈正相关，POD活性与SOD活性呈极显著正相关(R2=0.969)，POD与CAT活性呈正相关(R2=0.020)，CAT与SOD活性呈正相关(R2=0.425)。一方面，谷子幼苗在缺氮胁迫下地上部鲜重和干重分别比CK减少73.6%和34.6%，显著抑制幼苗叶片的生物量积累；幼苗叶片的叶绿素a、b含量和叶绿素总含量均显著下降，抑制叶片叶绿素的合成；谷子幼苗根系的总根长、根总投影面积、根表面积和根平均直径比CK均显著增加，缺氮胁迫促进了幼苗根系的伸长生长。另一方面，缺氮胁迫下谷子幼苗叶片MDA含量显著增加，活性氧累积，3种抗氧化酶活性均显著降低，膜脂过氧化，谷子幼苗生长受到显著抑制。 |
| 关键词: 谷子 缺氮 幼苗生长发育 逆境胁迫 氧化损伤 |
| DOI：10.11841/j.issn.1007-4333.2022.03.03 |
| 投稿时间：2021-04-01 |
| 基金项目:国家重点研发计划(2019YFD1001700)；河北省重点研发计划(20326416D)；河北省农林科学院创新工程(2019-4-2-2)；河北省杂粮杂豆产业技术体系(HBCT2018070205) |
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| Effects of nitrogen deficiency stress on the growth of foxtail millet seedlings |
|
LU Yiwei,CUI Jihan,GUO Shuai,LI Shunguo,XIAO Nuoya,LIU Hanshuang,LIU Meng,XIA Xueyan
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| (Millet Research Institute/National Millet Improvement Center/Hebei Coarse Grain Research Laboratory, Hebei Academy of Agriculture and Forestry Sciences, Shijiazhuang 050035, China) |
| Abstract: |
| In order to clarify the effects of nitrogen deficiency stress on the growth and development of millet seedlings, a millet variety ‘Jigu 45' was used as the test object. The hydroponic method was adopted at seedling stage and total nitrogen nutrient solution culture(15 mol/L N)was used as the control(CK), the changes of seedling biomass, root traits, leaf photosynthetic pigment content and physiological indexes under nitrogen deficiency(0 mol/L N, N0)stress were determined, and Pearson correlation analysis of biomass, chlorophyll and physiological indexes was performed. The results showed as follows: 1)The old leaves of seedlings showed the symptoms of leaf tip drying under nitrogen deficiency; Compared with CK, the plant fresh weight, dry weight and seedling height of millet seedlings under nitrogen deficiency stress decreased significantly. However, root traits such as underground fresh weight, underground dry weight, root/shoot ratio, total root length, root projection area, root surface area and average diameter were significantly improved. Compared with CK, chlorophyll a and b content of millet seedling leaves decreased by 32. 3% and 34. 5%, respectively, which inhibited significantly chlorophyll synthesis of seedling leaves under nitrogen deficiency stress. 2)Compared with CK, SOD, POD, CAT enzyme activities and soluble protein content of seedlings under nitrogen deficiency stress were reduced by 24. 9%, 43. 1%, 33. 9% and 7. 0% respectively. The content of MDA and total soluble sugar increased by 46. 2% and 92. 5%, respectively. 3)The correlation results showed that under nitrogen deficiency stress, soluble total sugar was positively correlated with underground dry fresh weight, POD activity was highly significant positively correlated with SOD activity(R2=0. 969). POD activity was positively correlated with CAT activity(R2=0. 020). CAT activity was positively correlated with SOD activity(R2=0. 425). On the one hand, under nitrogen deficiency, plant fresh weight and dry weight of millet seedlings decreased respectively by 73. 6% and 34. 6% compared with CK, which significantly inhibited leaf biomass accumulation of seedlings. Chlorophyll a, chlorophyll b and total chlorophyll content of seedling leaves decreased significantly, which inhibited chlorophyll synthesis of leaves. The total root length, total root projection area, root surface area and average root diameter of millet seedlings increased significantly, and root elongation and growth were promoted by nitrogen deficiency stress. On the other hand, under nitrogen deficiency stress, MDA content increased significantly and reactive oxygen species accumulated. Therefore, the activities of three antioxidant enzymes were decreased significantly and the membrane lipid was peroxidated in leaves of millet seedlings, which inhibited the growth of millet seedlings significantly. |
| Key words: millet nitrogen deficiency seedling growth and development adversity stress oxidative damage |
