不同盐度下红海榄植株中离子、氮和磷含量实验研究

Experimental Study on Ion,Nitrogen,and Phosphorus Concentrations in Rhizophora stylosa Plants under Different Salinity Conditions

于2019年3月1日至11月30日,在不同盐度胁迫下,开展了为期9个月的红海榄(Rhizophora stylosa)幼苗培养实验。在实验中,配制了总氮质量浓度为160 mg/L、总磷质量浓度为40 mg/L和盐度分别为0、5‰、10‰、15‰、20‰、30‰、40‰、50‰的实验用水。实验结束时,采集红海榄植株的根、茎和叶样品,测定根、茎和叶样品中的钠离子、钾离子、钙离子、镁离子、氯离子、全氮和全磷含量,分析灌溉水盐度与根、茎和叶样品中各种离子、全氮和全磷含量的关系。研究结果表明,随着灌溉水盐度的增大,被灌溉了9个月的红海榄植株根、茎和叶中的钠离子和氯离子含量不断增大,根中的钠离子和氯离子的富集速度和含量都大于茎和叶;在盐胁迫下,红海榄植株根、茎和叶选择性吸收钠离子而抑制钾离子的吸收;随着灌溉水盐度的增大,红海榄植株茎和叶中的钙离子含量呈单峰型变化,当灌溉水盐度为15‰时,其钙离子含量都达到最大值,根中的钙离子含量则波动减小,茎和根中的镁离子含量逐渐小幅增大,叶中的镁离子含量则在大幅减小;当灌溉水盐度为15‰时,红海榄植株茎的全氮含量最大,叶的全磷含量最大,当灌溉水盐度为20‰时,叶的全氮含量最大;灌溉水的盐度越大,红海榄植株根、茎和叶中的钠离子和氯离子含量越大,钾离子含量越小;灌溉水的盐度与红海榄植株根中的5种离子含量和全氮、全磷含量都显著相关,根、茎和叶中的钙离子含量与镁离子含量不相关。

A 9-month experiment of Rhizophora stylosa seedling cultivation was conducted under different salinity conditions from March 1 to November 30,2019.Water with a total nitrogen mass concentration of160 mg/L,total phosphorus mass concentration of 40 mg/L,and salinity of 0,5‰,10‰,15‰,20‰,30‰,40‰,and 50‰was tested.At the end of experiment,concentrations of sodium,potassium,calcium,magnesian and chloride ions,total nitrogen,and total phosphorus in the roots,stems and leaves of Rhizophora stylosa plants were measured,and the correlation among the salinity of irrigation water and concentrations of ions,total nitrogen,and total phosphorus of samples were analyzed.With the increase of the salinity of irrigation water,the concentrations of sodium and chloride ions in the roots,stems and leaves of Rhizophora stylosa plants increased during 9 months,and the enrichment speed and concentrations of sodium and chloride ions in roots were greater than those in stems and leaves.Under salt stress,sodium ion was selectively absorbed by roots,stems and leaves,and the absorption of potassium ion was inhibited.The concentrations of calcium ion in stems and leaves changed with a single-peak type,and the maximum value was observed when the salinity of irrigation water was 15‰,whereas the concentration of calcium ion in the roots was reduced undulately.The concentrations of magnesium ion slightly increased in stems and roots,but dramatically reduced in leaves.Under low salty stress(the salinity of irrigation water is 15‰or 20‰),the concentration of total nitrogen was the highest in stems and leaves,and the concentration of total phosphorus was the highest in leaves.The salinity of irrigation water was significantly correlated with concentrations of ions,total nitrogen,and total phosphorus,but the concentration of calcium ion was not correlated with the concentration of magnesium ion in roots,stems and leaves of Rhizophora stylosa plants.