Abstract: In order to study the response of leaf water potential and stomatal conductance to different degree of water stress in sea-buckthorn at the seedling stage, four kinds of soil water content were set up by potted water control experiment with 1 year old sea-buckthorn seedling, which were 75% ~ 80% of field capacity (W1, full water supply), 55% ~ 60% of field capacity (W2, light water stress), 35% ~ 40% of field capacity (W3, medial water stress), 25% ~ 30% of field capacity (W4, severe water stress). The leaf water potential, stomatal conductance, leaf temperature and meteorological factors were measured every 2 hours from 6:00 to 18:00 in cloudless and windless days. The results showed that the difference in leaf water potentials of four treatments was significant (P<0.05), following the order of W₁ (-1.77MPa)> W₂ (-1.90MPa)> W₃ (-2.11MPa)> W₄ (-2.34MPa). Moreover, positive linear correlation was found between the mean values of leaf water potential and soil water content (P<0.05).The values of stomatal conductance and leaf water potential had a significant linear correlation (P<0.05). The study contributes to better understanding on drought resistance mechanism of sea-buckthorn and provides technical support for sea-buckthorn afforestation in the northwest desert region.

Key words: water stress, sea-buckthorn, leaf water potential, stomatal conductance, soil water content

摘要： 为研究沙棘苗期叶水势和气孔导度对不同程度水分胁迫的响应规律,本研究通过盆栽控水试验,以1年生沙棘实生苗为试验材料,设置了4种土壤田间含水量: 75%~80%(W₁,充分供水)、55%~60%(W₂,轻度水分胁迫)、35%~40%(W₃,中度水分胁迫)、25%~30%(W₄,重度水分胁迫),选择晴朗无风的天气,于6:00-18:00每隔2 h测量叶水势、气孔导度(Gs)、气象因子和叶温。结果表明,各处理日平均叶水势差异显著(P<0.05):W₁(-1.77 MPa)> W₂(-1.90 MPa)> W₃(-2.11 MPa)> W₄(-2.34 MPa)。沙棘日平均叶水势与土壤含水量,平均叶水势与气孔导度均呈显著线性正相关关系(P<0.05)。本研究结果有助于进一步认识沙棘苗期的抗旱机理,为西北荒漠地区沙棘造林提供技术支撑。

关键词: 水分胁迫, 沙棘, 叶水势, 气孔导度, 土壤含水量