生物炭基肥对干旱胁迫复水胡枝子叶水势的影响

Effects of a Biochar-based Fertilizer on the Leaf Water Potential of Lespedeza bicolor Seedlings under Drought Stress and Rewatering

探究生物炭基肥对干旱胁迫下胡枝子幼苗叶水势的影响,为胡枝子的栽培利用提供理论和技术支撑。通过温室盆栽试验,研究不同生物炭基肥添加量(750、1 500、2250 kg/hm^(2))和不同水分处理[100.00%Soil Relative Water Content(SRWC),87.84%SRWC,70.00%SRWC,52.16%SRWC,40.00%SRWC]对胡枝子叶水势的影响。结果表明:在750、1500、2250 kg/hm^(2)生物炭基肥添加条件下,随着干旱胁迫程度加剧,植物幼苗叶水势逐渐下降,水分胁迫指数逐渐上升;40.00%SRWC处理组的植株叶水势下降幅度较大,15和30d干旱历时下,3个生物炭基肥处理的胡枝子幼苗平均叶水势分别比对照下降了0.69和0.48 MPa。旱后复水条件下植物叶水势逐渐恢复,恢复情况与干旱程度、干旱历时紧密相关。复水6d后,除15 d干旱历时下52.16%SRWC和40.00%SRWC处理的胡枝子幼苗叶水势未完全恢复到对照水平外,其余处理组的植株叶水势均恢复到接近或超过对照水平,出现补偿效应和超补偿效应。

To research the response characteristics of the leaf water potential of Lespedeza bicolor seedlings under drought stress and rewatering,various amounts of biochar-based fertilizer have been applied.Pot experiments were conducted in a greenhouse to estimate the effects of different application rates of biochar-based fertilizer(750,1500,and 2250 kg×hm^(-2)),various levels of water stress(100.00%,87.84%,70.00%,52.16%,and 40.00%soil relative water content),and rewatering conditions on the L.bicolor seedling leaf water potential.The results revealed that severe drought conditions led to a decrease in leaf water potential and an increase in the water stress index of L.bicolor seedlings when biochar-based fertilizer was ap-plied at rates of 750,1500,and 2250 kg×hm^(-2).Among the treatments,the lowest leaf water potential in seedlings was ob-served under the 40.00%SRWC treatment.In particular,applying three fertilizer levels(750,1500,and 2250 kg×hm^(-2))re-sulted in a decrease of 0.69 MPa and 0.48 MPa in the average leaf water potential after 15 d and 30 d of drought stress,re-spectively.However,the leaf water potential of L.bicolor seedlings exhibited recovery over time upon rewatering.A strong correlation was found between the severity of drought stress and the duration of the drought.In contrast,after six days of re-watering,the leaf water potential of L.bicolor seedlings subjected to 15 days of drought stress did not fully recover to the control level in the 52.16%and 40.00%SRWC treatments.However,the leaf water potential of L.bicolor seedlings in the other treatments recovered to the control level and even exhibited compensatory and super-compensatory effects.