3种梓树属植物的抗涝性

选取3种梓树属植物楸树(QS2)、滇楸(DQ72)、梓树(ZS1)的优良单株为试材,淹水胁迫30 d,排水恢复10 d,研究三者的抗涝性差异。结果显示:淹水胁迫导致QS2、DQ72和ZS1的植株形态发生了明显变化,包括叶片生长速度减缓、变黄、枯萎和脱落,以及皮孔膨大、根系死亡等。试验结束时,DQ72、QS2和ZS1对照植株的成活率均为100%,而淹水植株则分别为85%、65%和0。淹水胁迫显著抑制了DQ72、QS2和ZS1的苗高与地径生长,以及茎、叶、根的生物量积累。试验结束时,DQ72、QS2和ZS1苗高的淹水变化率分别为44.12%、53.57%和72.28%,地径淹水变化率分别为51.11%、57.83%和77.55%,总生物量淹水变化率分别为55.89%、57.91%和66.64%。DQ72、QS2和ZS1的叶片气体交换参数(净光合速率(P_n)、蒸腾速率(T_r)、气孔导度(G_s)、胞间CO_2浓度/环境CO_2浓度(C_i/C_a)、潜在水分利用效率(W_(U,E)))和叶绿素荧光参数(可变荧光F_v、可变荧光/最大荧光(F_v/F_m)、可变荧光/初始荧光(F_v/F_o))对淹水胁迫的响应显著不同。30 d时的淹水变化率显示,DQ72的光合与叶绿素荧光系统受淹水胁迫的损伤最小,QS2次之,ZS1最大。综合分析淹水胁迫下,DQ72、QS2和ZS1的植株成活率、苗高与地径生长、生物量积累,以及叶片气体交换和叶绿素荧光参数的变化,可以确定,DQ72的抗涝性最强,QS2居中,且与DQ72差异不显著,ZS1的抗涝性显著弱于DQ72和QS2。

Flood-tolerance Comparison of Three Tree Species belonging to Catalpa

Flood-tolerance comparison of superior individuals from three tree species,Catalpa bungei (QS2),C.fargesii Bur.f.duclouxii (DQ72) and C.ovata (ZS1),were performed by 30-d flooding treatment,and followed by lO-d drainage and recovery period.QS2,DQ72 and ZS1 were obviously influenced in morphology when subjected to flooding stress,including retarded leaf development,chlorosis and abscission of leaves,development of hypertrophied lenticels,as well as roots death.The survival rate of plants from DQ72,QS2 and ZS1 was 100％ in CK,while 85％,65％ and 0,respectively,were observed in its flooded plants.Soil flooding significantly affected height and root-collar diameter growth adversely,as well as stem,leaf and root biomass accumulation in all flooded plants of DQ72,QS2 and ZS1.After recovery,the rates of change due to flooding in height growth were 44.12％,53.57％ and 72.28％ in DQ72,QS2 and ZS1,respectively,and for root-collar diameter growth,they were 51.11％,57.83％ and 77.55％,respectively.For total biomass,these values were 55.89％,57.91％ and 66.64％,respectively.Significantly different responses to soil flooding were investigated in gas exchange (net photosynthesis Pn,transpiration Tr,stomatal conductance Gs,ratio of internal and atmospheric CO2 concentrations Ci/Ca,intrinsic water use efficiency WU,E) and chlorophyll fluorescence (variable fluorescence Fv,ratio of variable fluorescence to maximum fluorescence Fv/Fm,ratio of variable fluorescence to initial fluorescence Fv/F.) of the flooded plants from DQ72,QS2 and ZS1.Change rates due to flooding on 30 th day indicated that photosynthesis and chlorophyll fluorescence system hurts induced by flooding stress were occurred lightest in DQ72,severest in ZS1 and middle in QS2.According to the performance of height and root-collar growth,biomass accumulation,survival rate,as well as gas exchange and chlorophyll fluorescence system,DQ72 displayed the strongest flood-tolerance.QS2 has the second strong flood-tolerance and insignificantly differed with DQ72.Flood-tolerance of ZS1 was significantly lower than DQ72 and QS2.