钾镁胁迫对巴西橡胶树花药苗生理特性及叶绿体超微结构的影响

本研究通过营养液培养试验,重点揭示橡胶树的部分生理特性、叶绿体超微结构等指标对钾、镁缺乏的响应机制。以巴西橡胶树热研7-33-97花药苗（简称花药苗）为试验材料,设置缺钾镁（-K-Mg）、缺钾（-K）、缺镁（-Mg）、正常（CK）4个处理,测定花药苗株高、茎粗、叶绿素含量、钾镁含量、可溶性糖组分、叶绿体超微结构等指标。结果表明：（1）与CK相比,-K-Mg处理显著降低花药苗株高和茎粗,降幅分别为12.2%和15.7%,叶片出现衰亡、凋落现象;-K-Mg、-K和-Mg处理叶片的光合色素含量均显著下降（P<0.05）。（2）钾、镁胁迫均显著降低花药苗各器官钾、镁含量,钾供应极显著提高各器官镁含量,而镁供应对各器官钾含量无显著影响。（3）与CK相比,-K-Mg、-K、-Mg处理的葡萄糖、蔗糖和果糖含量均显著升高,钾、镁交互作用对果糖含量影响显著。（4）与CK相比,-K-Mg、-K及-Mg处理显著降低花药苗叶绿体长度,降幅分别为26.9%、38.1%和19.6%;嗜饿体数目显著增加,增幅分别为211.8%、767.7%和138.2%;缺镁条件下叶绿体中淀粉粒数目增加。综上所述,钾、镁胁迫对橡胶树花药苗生长、叶绿体发育均具有明显的抑制作用,钾、镁供应对2种元素吸收方面存在明显的钾对镁的单方面拮抗。生产上重视钾、镁的合理施用及其二者的交互作用,对改善橡胶树的生长状况具有重要的实践意义。

Effects of Potassium and Magnesium Deficiency on Leaf Physiological Characteristics and Chloroplast Ultrastructure of Anther Culture Seedling of Rubber Tree (Hevea brasiliensis)

A hydroponic experiment was conducted to clarify the response mechanism of potassium and magnesium deficiency affecting on some physiological characteristics and chloroplast ultrastrucure of rubber trees. The anther culture seedling of Hevea brasiliensis 7-33-97 was selected as the research material, and four treatments of -K-Mg, -K, -Mg, CK (control) were designed. The plant height, stem diameter, chlorophyll content, nutrients concentration, soluble sugar components and chloroplast ultrastrucure of rubber seedling were analyzed, respectively. Compared with CK, the plant height and stem diameter significantly decreased by 12.2% and 15.7% respectively, and the premature senescence and dying off of seedling leaves appeared under the condition of -K-Mg. The chlorophyll content of the leaf under -K-Mg, -K and -Mg significantly decreased (P<0.05). The concentrations of potassium and magnesium in different organs decreased significantly under potassium and magnesium deficiency. Potassium supply decreased significantly magnesium concentrations in different organs, while no significant effects in potassium concentration by the magnesium supply. Treatments of -K-Mg, -K and -Mg significantly increased the contents of glucose, sucrose and fructose in seedling leaves compared with CK. There was significant effect of interaction between K and Mg on the content of fructose. The treatments of -K-Mg, -K and -Mg significantly decreased chloroplast length by 26.9%, 38.1% and 19.6%, and significantly increased the number of plastoglobulus by 211.8%, 767.7% and 138.2%, respectively. Meanwhile, the treatment of -Mg significantly increased the number of starch granules. In summary, the deficiency of potassium and magnesium significantly inhibited the development of plant growth and chloroplast. Potassium had an antagonism effect on the absorption of magnesium under normal magnesium level. Therefore, the rational application of potassium and magnesium and the interaction should be emphasized in production, which could improve the plantation condition of rubber trees.