以1和3 a生头状沙拐枣为研究对象,采用盆栽试验,研究了不同灌水处理(田间持水量的30%、40%、50%、60%和85%)下头状沙拐枣的生长和生理变化特征。结果表明:(1)随灌溉量降低,1和3 a生头状沙拐枣的株高、冠幅、基茎、同化枝直径和整株生物量均显著下降。在不同生长期,生物量的主要累积器官茎的干物质分配比例随灌溉量降低而显著下降,根系干物质分配比例却显著增加,但灌溉量过高或过低均不利于3 a生头状沙拐枣种子生产;(2)灌溉量较低时,头状沙拐枣的根冠比、叶绿素和MDA含量均相对较高,质膜损伤严重,但植物可通过累积大量的脯氨酸进行渗透调节。随灌溉量增加,质膜损伤减轻,脯氨酸和可溶性糖累积存在明显的补偿作用,但在最高灌溉量下叶绿素含量显著下降;(3)综合适应性评价结果为田间持水量的60%〉85%〉50%〉40%〉30%。可见,灌溉量为田间持水量的60%时头状沙拐枣综合适应性最好,可作为头状沙拐枣在当地定植的推荐灌溉量。
The pot experiment was conducted to study the changes of plant growth and physiological characteristics of 1- and 3-year-old Calligonum caput-medusae under different irrigation treatments( 30%,40%,50%,60%,and 85% field water capacity( FC)),and find out the suitable water condition for the plant growth. The plant height,canopy,base diameter,assimilating branch diameter,and the biomass of whole plant declined significantly with the decreasing of irrigation amount for both 1- and 3-year-old plants. At both growth stages,stem was the main organ for dry matter accumulation. The dry matter allocation proportion of stem was positively affected by the increasing irrigation amount,but that was negatively for root. However,C. caputmedusae of 3-year-old could not produce fruit at the lowest irrigation level,and the fruit yield was significantly lower at 85% FC than that by other treatments. The assimilating branches had high chlorophyll and MDA contents under lower irrigation treatment. The damage of plasmamembrane was serious under drought condition.However,there was a large number of proline accumulated in the assimilating branches to adapt to water stress.The damage of plasmamembrane was reduced with the increasing of irrigation,and the proline and soluble sugar accumulations were complemented each other. The chlorophyll content decreased significantly under the highest irrigation treatment for both 1- and 3-year-old C. caput-medusae. Based on all of the above determined indexes,the comprehensive adaptability was in the following order: 60% FC 85% FC 50% FC 40% FC 30%FC. Therefore,the medium irrigation level( 60% FC) is appropriate for establishing C. caput-medusae seedlings in this area.