亚硒酸钠处理对油菜幼苗相关生理指标的影响

Effects of Sodium Selenite Treatment on Physiological Indexes Related to Oilseed Rape Seedlings

探究不同浓度亚硒酸钠(Na(2)SeO_(3))对油菜幼苗生长发育和生理特性的影响,揭示油菜幼苗对硒胁迫的生理反应机制,为富硒油菜育种及生产实践提供理论依据。采用盆栽法培养幼苗1周,再选用0.000、0.010、0.020、0.050、0.075、0.100 g/kg的Na(2)SeO_(3)浓度处理幼苗2周,后测定幼苗中相关形态、生理指标。与对照相比,随着Na(2)SeO_(3)浓度增加,油菜幼苗的生长、生理指标变化包括:(1)Na(2)SeO_(3)处理浓度为0.020 g/kg时,油菜幼苗的株高、叶长、干重、鲜重增加,促进幼苗的生长,而处理浓度为0.100 g/kg时则抑制幼苗生长。(2)Na(2)SeO_(3)处理浓度为0.075 g/kg时,叶绿素a、叶绿素b、叶绿素a+b、类胡萝卜素的含量均显著升高,分别上升了36.85%、69.41%、53.14%、156.08%(P<0.05)。(3)Na(2)SeO_(3)处理浓度为0.020 g/kg时,油菜幼苗中可溶性糖、脯氨酸、过氧化氢含量显著升高,分别增加了47.38%、377.21%、135.93%(P<0.05);丙二醛(MDA)含量呈现下降的趋势,处理浓度为0.075、0.100 g/kg时MDA含量显著下降了25.47%、26.24%(P<0.05)。(4)Na(2)SeO_(3)处理浓度为0.020~0.075 g/kg时,抗坏血酸过氧化物酶(APX)活性显著升高35.10%~72.02%(P<0.05),处理浓度为0.100 g/kg时显著降低了99.71%(P<0.05);Na(2)SeO_(3)处理浓度为0.020~0.100 g/kg时,过氧化物酶(POD)活性显著上升23.24%~78.42%(P<0.05),超氧化物歧化酶(SOD)活性显著下降22.39%~31.22%(P<0.05)。(5)Na(2)SeO_(3)浓度与类胡萝卜素含量、O_(2)^(·-)产生速率呈显著正相关关系(P<0.01),与幼苗干重、鲜重、MDA含量和SOD活性呈极显著负相关关系(P<0.01)。因此,不同Na(2)SeO_(3)处理浓度对油菜幼苗的生长生理特性有不同程度的影响,其中以0.020 g/kg Na(2)SeO_(3)浓度处理的效果最佳。

In this paper,the effects of different concentrations of sodium selenite(Na(2)SeO_(3))on the growth,development and physiological characteristics of oilseed rape seedlings were investigated,the mechanism of physiological response of oilseed rape seedlings to selenium stress was revealed,to provide a theoretical basis for the breeding of selenium-enriched oilseed rape and the production practice.Seedlings were cultivated in pots for 1 week,and then treated with Na(2)SeO_(3) at concentrations of 0.000,0.010,0.020,0.050,0.075,0.100 g/kg for 2 weeks,and then relevant morphological and physiological indexes were measured in the seedlings.Compared with the control,the changes in growth and physiological indexes of oilseed rape seedlings with the increase of Na(2)SeO_(3) concentration included:(1)The increase of plant height,leaf length,dry weight and fresh weight of oilseed rape seedlings with Na(2)SeO_(3) treatment concentration of 0.020 g/kg promoted the growth of seedlings,while the treatment concentration of 0.100 g/kg inhibited the growth of seedlings.(2)When the concentration of Na(2)SeO_(3) was 0.075 g/kg,the contents of chlorophyll a,chlorophyll b,chlorophyll a+b and carotenoids increased significantly by 36.85%,69.41%,53.14% and 156.08%,respectively(P<0.05).(3)When the concentration of Na(2)SeO_(3) was 0.020 g/kg,the contents of soluble sugar,proline and hydrogen peroxide in rapeseed seedlings increased significantly by 47.38%,377.21%and 135.93%,respectively(P<0.05).The MDA content showed a decreasing trend,and the malondialdehyde(MDA)content decreased significantly by 25.47% and 26.24% at the treatment concentrations of 0.075 g/kg and 0.100 g/kg(P<0.05).(4)When the concentration of Na(2)SeO_(3) was 0.020-0.075 g/kg,the ascorbate peroxidase(APX)activity increased significantly by 35.10%-72.02%(P<0.05),and decreased by 99.71%when the treatment concentration was 0.100 g/kg(P<0.05).When the concentration of Na(2)SeO_(3) was 0.020-0.100 g/kg,the peroxidase(POD)activity increased significantly by 23.24%-78.42%(P<0.05).The activity of superoxide dismutase(SOD)decreased significantly by 22.39%-31.22%(P<0.05).(5)The concentration of Na(2)SeO_(3) was significantly positively correlated with carotenoid content and O_(2)^(·-)production rate(P<0.01),and negatively correlated with dry weight,fresh weight,MDA content and SOD activity of seedlings(P<0.01).Therefore,different Na(2)SeO_(3) concentrations had different effects on the growth and physiological characteristics of rapeseed seedlings,and the best effect was achieved at 0.020 g/kg Na(2)SeO_(3) concentration.