滴灌甜菜对块根膨大期水分亏缺的补偿性响应

为探讨滴灌甜菜块根膨大期干旱胁迫及复水的生长补偿效应,设置70%(T1)、50%(T2)和30%(T3)田间持水量,调查块根膨大期缺水对滴灌甜菜产量、农艺性状以及理化指标的影响。结果表明,当土壤为30%田间持水量时,甜菜产量比70%和50%田间持水量分别提高51.7%和17.6%,产糖量分别提高48.7%和7.7%。与70%田间持水量相比,50%和30%田间持水量条件下,块根膨大期甜菜电导率、脯氨酸以及过氧化物酶活性均在复水1 d时显著增加。主成分分析表明,细胞膜透性、抗氧化酶活性、渗透调节物质以及农艺特性共同调控块根膨大期甜菜抵御干旱胁迫,其中块根可溶性糖含量不能作为甜菜抗旱性鉴定的指标。因此,滴灌甜菜块根膨大期,当土壤含水量下降至田间持水量的30%时及时补充灌溉,不但不影响甜菜生长,还有利于增加块根含糖量。

Compensation Response of Drip-Irrigated Sugar Beets (Beta vulgaris L.) to Different Water Deficits during Storage Root Development

The objective of this experiment was to investigate the compensation response of drip-irrigated sugar beets under drought stress and rewatering during storage root development. The experiment at treatments were field capacity of 70% (T1), 50% (T2), and 30% (T3). The yield, agronomic characteristics, and physical and chemical properties of the beet roots were measured. The sugar yield and technological sugar yield in T3 treatment were 51.7, 17.6% and 48.7%, 7.7% more than these in T1 and T2 treatments, respectively. At one day after rewatering, electrical conductivity, proline content, POD activity were significantly greater in T2 and T3 treatments than in T3 treatment during storage root development. Principal component analysis showed that a regulation system consisted of membrance permeability, antioxidant enzyme activity, osmotic adjustment and agronomic characteristics resisting drought stress, among which soluble sugar content can not be used as an indicator of drought resistance indentification of sugar beet during the devevelopment of sugar beet storage roots. Therefore, supplemental irrigation should be carried out promptly when the soil water content drops to 30% of field capacity during storage root development, which is beneficial to increase the sugar content and do not affect the growth of sugar beet.