不同干旱胁迫对黑果腺肋花楸幼苗生长及光合特性的影响

Effects of Different Drought Stress on Seedling Growth and Photosynthetic Characteristics of Aronia Melanocarpa

为探究黑果腺肋花楸幼苗对不同干旱胁迫下的生长及光合特性的响应,以1 a生黑果腺肋花楸幼苗为试材,采用盆栽控水试验,进行不同干旱处理[轻度(LS)、中度(MS)、重度(SS)],于干旱处理第30 d测定其生长及光合特征参数,并对各项指标进行相关性分析。结果表明:干旱胁迫抑制了黑果腺肋花楸幼苗生长及光合能力,与对照相比,干旱胁迫处理导致生物量、茎粗、叶面积等生长指标和净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、胞间CO_(2)浓度(Ci)、水分利用效率(WUE)、叶绿素a(Chla)、类胡萝卜素含量(Car)等光合参数指标显著下降;株高、叶绿素b(Chlb)、总叶绿素(T Chl)含量保持对照水平;根冠比(R/S)显著增加;LS、MS处理叶片相对含水量(RWC)和最大光化学效率(Fv/Fm)与对照相比无显著差异;生长指标与Pn呈极显著正相关;Pn与Gs、Ci呈极显著正相关,这表明“气孔限制”是干旱胁迫下黑果腺肋花楸幼苗Pn下降的主要原因。研究发现,黑果腺肋花楸在LS~MS处理(土壤含水量为田间持水量的40%~60%)下R/S最佳,将更多的资源分配给地下根部,并通过提高叶片Fv/Fm值和调节Gs、保持较高的RWC来适应干旱环境,在SS(土壤含水量为田间持水量的20%)处理下虽受到较严重的影响,但仍能够生存且维持生长,表明黑果腺肋花楸是具有一定抗旱性的树种。

In order to explore the growth and photosynthetic characteristics response of A.melanocarpa seedlings to drought stress,in this study,the one-year-old seedlings of A.melanocarpa was used as study material and a water control experiment was conducted at greenhouse.Four treatments,including well-irrigated(CK),mild drought stress(LS),moderate drought stress(MS),severe drought stress(SS),were applied for 30d.At the end of the experiment,the growth and photosynthetic characteristic parameters were investigated and the correlation of each index was analyzed.The results indicated that drought stress inhibited growth and photosynthetic capacity of A.melanocarp seedlings.Compared with CK,growth performance(shoot and root biomass,stem diameter,leaf area)and photosynthetic parameters,including net photosynthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr),intercellular CO_(2) concentration(Ci),water use efficiency(WUE),content of Chlorophyll a(Chl a)and Carotenoid were decreased significantly with the intensity of drought stress.However,no significant difference was observed in plant height,content of Chlorophyll b(Chlb)and total Chlorophyll.A significant increase in root/shoot ratio(R/S)was observed,but there were no significant change in the RWC and Fv/Fm under mild and moderate drought stress compared to the control treatment.There was a significant positive correlation between growth index and Pn.And there was a significant positive correlation between Pn and Gs and Ci,suggesting that stomatal restriction was the main reason for the decrease of leaf photosynthesis under drought stress.The results showed that R/S was the best under LS-MS treatment(soil water content was 40%to 60%of field water capacity),under which more resources were allocated to underground roots,the leaf Fv/Fm value was increased and the RWC was maintained by adjusting Gs and increasing LEAF Fv/Fm.Under SS treatment(soil water content was 20%of field water capacity),A.melanocarp seedlings were severely affected,but it still could survive and maintain its growth,which indicated that it was a drought resistant tree.