不同年代梭梭同化枝δ^(13)C值与解剖结构及生理指标的关系

The Relationship Between δ^(13)C Values and Anatomical Structure and Physiological Indexes of Assimilating Shoots of Different-Aged Haloxylon ammodendron

植物叶片的稳定碳同位素组成(δ^(13)C)指示了其水分利用效率的高低,反映植物对干旱环境的适应能力。以民勤梭梭为试验材料,通过测定不同年代梭梭同化枝δ^(13)C、解剖结构、含水量、叶绿素含量、渗透调节物质(脯氨酸、可溶性糖)含量和C、N、P、K含量等,分析梭梭同化枝δ^(13)C随年代变化规律及其与解剖结构、生理指标之间关系。结果表明:1)梭梭同化枝δ^(13)C值的变化范围在-0.1565%~-0.1385%,随着年代的增加,梭梭同化枝δ^(13)C值呈先升高后降低再升高的趋势,在20世纪70年代出现峰值。2)除角质层和导管孔径,不同年代梭梭同化枝解剖结构指标差异显著(P<0.05),变异系数变化范围为5.19%~21.53%;不同年代梭梭同化枝δ^(13)C值与解剖结构各指标之间相关性均未达到显著水平(P>0.05)。3)不同年代梭梭同化枝δ^(13)C值与全氮含量呈显著负相关(P<0.05)。以上研究结果表明,叶片δ^(13)C值可以反映植物生长环境及本身水分的亏缺程度;N含量显著影响民勤不同年代梭梭同化枝δ^(13)C值。

The stable carbon isotope composition(δ^(13)C)of plant leaves indicates the water use efficiency of plants and reflects the adaptability of plants to arid environment.In this study,Haloxylon ammodendron occurring in Minqin of Gansu Province was used as experimental material,theδ^(13)C value,water content,chlorophyll content,contents of osmotic regulatory substances(proline and soluble sugar),carbon,nitrogen,phosphorus and potassium of H.ammodendron assimilating shoots in different ages were determined,and the relationships between theδ^(13)C and physiological indexes were analyzed.The results showed that 1)theδ^(13)C values of H.ammodendron assimilating shoots varied from-0.1565%to-0.1385%.With the increase of age,theδ^(13)C values increased first,then decreased and then increased,and peaked in the 1970s.2)Except for cuticular and pore of catheter,there were significant differences in anatomical structure indexes of the shoots in different ages(P<0.05),and the variation coefficient ranged from 5.19%to 21.53%.There was no significant correlation between theδ^(13)C values of the shoots in different ages and anatomical structure indexes(P>0.05).3)There was a significant negative correlation between theδ^(13)C values of the shoots in different ages and total nitrogen content(P<0.05).Theδ^(13)C values of the leaves could reflect the growing environment and the degree of water deficit in plants.Nitrogen content significantly affected theδ^(13)C values of H.ammodendron assimilating shoots with different ages.