海水胁迫下藜麦根系形态发育及生理响应

Morphological Development and Physiological Response of Quinoa Roots under Seawater Stress

筛选和培育耐盐植物是开发利用滨海盐渍土的重要途径。本试验在砂培条件下,研究不同稀释配比的海水(0、20%、30%、40%、50%、60%和70%)对藜麦植株生长、根系形态结构及生理特性的影响。结果表明:低于30%海水胁迫下,藜麦地上部生长受影响较小,株高和叶面积有所降低,茎粗和地上部生物量并没有受到显著影响,而根系总根长、最大根长、根表面积、根体积、根系平均直径及根尖数均表现出降低趋势;随着海水浓度的进一步增加,地上部和地下部生长均受到不同程度的抑制,其中对地下部的抑制作用大于地上部,根冠比逐渐降低。与根系形态发育相比,藜麦根系生理活性的变化在耐盐过程中起着更为重要的作用,根系活力随海水浓度的增加依次升高,尤其在高浓度海水胁迫下,表现出较强的根系活力。根系超氧化物歧化酶(SOD)和过氧化物酶(POD)活性随着海水浓度的增加先升高后降低,分别在30%和40%浓度下达到最大值;过氧化氢酶(CAT)活性呈逐渐升高的趋势;丙二醛(MDA)含量在0~40%海水浓度下较为稳定,大于50%时显著上升。盐胁迫下藜麦根系渗透调节物质含量发生显著变化,可溶性蛋白含量随海水浓度的增加呈先升后降趋势,40%海水浓度下达到最大值;根系脯氨酸含量呈逐渐升高的趋势。

Selection and cultivation of salt-tolerant plants is an important way to develop and utilize coastal saline soil.In this study,the effects of different dilution ratio of seawater(0,20%,30%,40%,50%,60%,70%)on the growth,morphological structure and physiological characteristics of the root system of quinoa were studied under the condition of sand culture.The results showed that under seawater stress of less than 30%,the above-ground growth of quinoa was less affected,plant height and leaf area decreased,stem diameter and above-ground biomass were not significantly affected,while the total root length,maximum root length,root surface area,root volume,average root diameter and root tip numbers showed a decreasing trend.With the further increase of seawater concentration,the growth of above-ground and under-ground parts were inhibited to varying degrees,among which,the inhibition to under-ground parts was greater than that of above-ground parts,and the root-shoot ratio decreased gradually.Compared with the development of root morphology,the change of physiological activity of quinoa root system played a more important role in salt tolerance.The root activity increased with the increase of seawater concentration,especially under high seawater stress.The activity of superoxide dismutase(SOD)and peroxidase(POD)in roots first increased and then decreased with the increase of seawater concentration,reaching the maximum value at 30%and 40%concentration,respectively.The activity of catalase(CAT)increased gradually,and the content of malondialdehyde(MDA)in roots was stable at 0~40%seawater concentration,but increased significantly when it was higher than 50%.The content of osmoregulation substance in quinoa root system changed significantly under salt stress.The content of soluble protein increased firstly and then decreased with the increase of seawater concentration and reached the maximum value under 40%seawater concentration.The content of proline in root system increased gradually.