水分胁迫下水肥耦合对矮砧富士幼树生长及保护酶活性的影响

Effects of water and fertilizer coupling on growth and protective enzyme activities of dwarf rootstock Fuji sapling under water stress

为了探究滴灌条件下20%θ_(f)、40%θ_(f)水分胁迫与N、P、K营养元素耦合对矮砧富士幼树生长生理的影响及各种保护酶活性的抗旱响应,于2019—2020年以3 a矮砧富士幼树为试材,采用“3414”不完全正交设计方案开展盆栽试验,对处理后的矮砧富士幼树形态指标、渗透调节物质、保护酶活性及丙二醛(MDA)含量等变化进行分析。结果发现:在轻度(40%θ_(f))水分胁迫下施用N 150 mg·kg^(-1)时,矮砧富士幼树的新梢生长量降幅最小,为9.95%;施用P 70 mg·kg^(-1)时叶面积降幅最小;施用K 250 mg·kg^(-1)相对叶绿素含量不降反增,升高了41.8%;MDA含量在施用P 35 mg·kg^(-1)时降幅最小,为45.76%;相对电导率在施用P 70 mg·kg^(-1)时降幅最小,为15.66%。在重度(20%θ_(f))水分胁迫下施用N 150 mg·kg^(-1)新梢生长量降幅最小,为14.71%;施用P 70 mg·kg^(-1)时叶面积降幅最小,为7.77%;施用P 70 mg·kg^(-1)时相对叶绿素含量降幅最小,为19.77%,MDA含量在施用N 100 mg·kg^(-1)、P 70 mg·kg^(-1)、K 250 mg·kg^(-1)时降幅最小,为61.32%;相对电导率在施用P 105 mg·kg^(-1)时升高6.49%。在轻、重度干旱胁迫下,施用N 100 mg·kg^(-1)和K 125 mg·kg^(-1)时叶片水势差维持在中等干旱(0.5~1.0 Mpa)水平,利于矮砧富士幼树生长各项形态指标保持正常水平。在轻度(40%θ_(f))水分胁迫下,矮砧富士幼树的渗透调节物质:脯氨酸含量在N 150 mg·kg^(-1)时升幅最明显(157.19%);可溶性糖含量在N 100 mg·kg^(-1)、P 70 mg·kg^(-1)、K 250 mg·kg^(-1)时升幅最大,为112.01%;保护酶活性:POD活性在N 100 mg·kg^(-1)时升幅最明显(147.26%)、SOD活性在N 100 mg·kg^(-1)时升幅最明显(217.92%)。在重度(20%θ_(f))水分胁迫下,脯氨酸含量在N 100 mg·kg^(-1)、P 70 mg·kg^(-1)、K 250 mg·kg^(-1)时升幅最明显(156.95%)、可溶性糖含量在N 100 mg·kg^(-1)、P 70 mg·kg^(-1)、K 250 mg·kg^(-1)时升幅最大(131.08%);POD活性在N 100 mg·kg^(-1)、P 70 mg·kg^(-1)、K 250 mg·kg^(-1)时升幅最明显(180.37%);SOD活性在N 50 mg·kg^(-1)时升幅最明显(973.95%)。在N(50、100 mg·kg^(-1))、P(35、70 mg·kg^(-1))、K(125 mg·kg^(-1))交互作用下新梢生长量、叶面积、相对叶绿素含量及叶片水势差等指标优于单独施用N、P、K的抗旱效果;MDA含量和相对电导率在N 100 mg·kg^(-1)、P 70 mg·kg^(-1)、K 125、250 mg·kg^(-1)时的抗旱效果优于单独施用N、P、K;渗透调节物质在N 100 mg·kg^(-1)、P 70 mg·kg^(-1)、K 250、375 mg·kg^(-1)时,保护酶活性在N 100、150 mg·kg^(-1)、P 70 mg·kg^(-1)、K 250 mg·kg^(-1)时抗旱效果优于单独施用N、P、K。在受到干旱胁迫时,若超出N、P、K适宜用量范围则会造成果树生理干旱,不利于果树生长。

In order to investigate the effects of 20%θ_(f) and 40%θ_(f) water stress coupled with elements N,P and K on growth physiology and drought resistance of Fuji sapling under drip irrigation,a pot experiment was carried out using Fuji sapling with 3 a short stocks as experimental materials in 2019-2020,using incomplete orthogonal design scheme“3414”.Morphological indexes,osmotic regulation substances,protective enzyme activities and MDA content of Fuji saplings treated by short stock were analyzed.The results showed that when N 150 mg·kg^(-1)was applied under mild(40%θ_(f))water stress,the minimum decrease of shoot growth was 9.95%.The relative chlorophyll content increased by 41.80%when K 250 mg·kg^(-1)was applied.The decrease of leaf area was the smallest under drought stress(40%θ_(f),20%θ_(f)).MDA content decreased by 45.76%when P 35 mg·kg^(-1)was applied.The relative conductivity decreased by 15.66%when P 70 mg·kg^(-1)was applied.When N 150 mg·kg^(-1)was applied under severe(20%θ_(f))water stress,the minimum decrease of shoot growth was 14.71%.When P 70 mg·kg^(-1)was applied,the leaf area decreased by 7.77%.When P 70 mg·kg^(-1)was applied,the relative chlorophyll content decreased 19.77%,and MDA content decreased 61.32%when N 100 mg·kg^(-1),P 70 mg·kg^(-1),and K 250 mg·kg^(-1).The relative conductivity increased by 6.49%when P 105 mg·kg^(-1)was applied.The leaf water potential difference maintained the medium drought level(0.5~1.0 MPa)when applying N 100 mg·kg^(-1)and K 125 mg·kg^(-1)under light and severe drought stress,which was conducive to the normal growth of various morphological indexes of Fuji saplings.Under mild water stress(40%θ_(f)),the osmotic adjustment substances of Fuji sapling increased by 157.19%at N 150 mg·kg^(-1),soluble sugar content at N 100 mg·kg^(-1),P 70 mg·kg^(-1),K At 250 mg·kg^(-1),the maximum increase is 112.01%;Protective enzyme activity:POD activity increased by 147.26%and SOD activity increased by 217.92%at N 100 mg·kg^(-1).Under severe(20%θ_(f))water stress,the increase of proline content was the most obvious at N 100 mg·kg^(-1),P 70 mg·kg^(-1),K 250 mg·kg^(-1),soluble sugar content at N 100 mg·kg^(-1),P 70 mg·kg^(-1),K At 250 mg·kg^(-1),the maximum increase is 131.08%;Protective enzyme activity:POD activity increased by 180.37%when N 100 mg·kg^(-1),P 70 mg·kg^(-1),K 250 mg·kg^(-1),SOD activity increased by 973.95%when N 50 mg·kg^(-1).Under N 50,100 mg·kg^(-1),P 35,70 mg·kg^(-1),K 125 mg·kg^(-1)interaction,shoot growth,leaf area,relative chlorophyll content and leaf water potential difference were better than those of N,P,K alone.MDA content and relative conductivity at N 100 mg·kg^(-1),P 70 mg·kg^(-1),K 125,250 mg·kg^(-1)were better than N,P,K alone.The drought-resistance effect of osmotic regulation substance at N 100 mg·kg^(-1),P 70 mg·kg^(-1),K 250,375 mg·kg^(-1)and the protective enzyme activity at N 100,150 mg·kg^(-1),P 70 mg·kg^(-1),K 250 mg·kg^(-1)was better than that of N,P,K alone.Under drought stress,if N,P,K exceed the appropriate dosage range,physiological drought will result in fruit trees,not conducive to the growth of fruit trees.