菌根化马尾松苗生长形态对干旱及复水响应

Response of Mycorrhizal Pinus massoniana Seedling on Growth Morphology to Drought and Rewatering

【目的】研究5种外生菌根真菌对马尾松(Pinus massoniana Lamb)幼苗在持续干旱和复水后生长、根系结构及养分吸收的影响,筛选优良菌根幼苗,为马尾松抗旱栽培育林提供科学依据。【方法】以马尾松幼苗为宿主,接种褐环乳牛肝菌7 (Suillus luteus)、褐环乳牛肝菌1 (Suillus luteus)、鸡油菌(Cantharellus cibarius)、彩色豆马勃(Pisolithus tinctorius)和土生空团菌(Cenococcum geophilum),以未接种的幼苗作为对照(CK),采用温室盆栽方法,对接种和未接种处理幼苗进行持续干旱7 d、14 d、21 d、28 d、35 d处理和持续干旱14 d、21 d、28 d后复水处理,比较分析幼苗的生长情况、根系结构及养分吸收情况。【结果】在持续干旱的情况下,菌株幼苗高度、地径、根长、根粗、侧根长、侧根数、根体积均明显高于对照,菌株幼苗的生物量和养分(N、P、K)含量均呈先增加后减少的趋势,并在胁迫的21 d达最大值;5种菌株幼苗的各项指标以接种褐环乳牛肝菌1的效果最好,与对照相比,苗高、地径分别增加37.8%和36.5%,生物量提高48.3%,根长、根粗、侧根长、侧根数、根体积分别提高67%、45%、204%、122%、450%,N、P、K含量分别增加129%、111%、212%。复水后菌株幼苗的恢复能力明显高于对照,轻度至中度干旱胁迫(14~21 d)后复水有利于菌株幼苗根系的生长发育,重度干旱胁迫(28~35 d)对幼苗产生一定伤害,复水后生长难以恢复;复水后褐环乳牛肝菌1显著促进幼苗根长和侧根数生长,胁迫14 d复水后达最大,增幅为59.6%、23.5%。持续干旱及复水后幼苗的生物量与P含量间呈显著正相关,接种彩色豆马勃复水后的幼苗生物量与根长、>5 cm侧根长度呈显著正相关。【结论】外生菌根真菌提高了幼苗生物量,促进其根部生长及养分吸收,增加持续干旱和复水后幼苗的抗逆性。在轻度干旱地区选择褐环乳牛肝菌1进行菌根化育苗,可提高造林成活率,增加苗木对干旱的适应性。

【Objective】The effects of five species of ectomycorrhizal fungi on the growth, root structure and nutrient uptake of Pinus massoniana Lamb.seedlings after persistent drought and re-watering are studied, and the best mycorrhizal seedlings are screened to provide a scientific basis for drought-resistant cultivation and reforestation of P.massoniana Lamb.【Method】Masson pine seedlings were used as hosts to inoculate with Suillus luteus, Suillus luteus 1, Cantharellus cibarius, Pisolithus tinctorius and Cenococcum geophilum.Taking the uninoculated seedlings as the control(CK), by greenhouse potted method, the inoculated and uninoculated seedlings were subjected to continuous drought treatment for 7 d, 14 d, 21 d, 28 d, 35 d and water treatment after continuous drought for 14 d, 21 d and 28 d, then the growth, root structure and nutrient absorption of seedlings were compared and analyzed.【Result】Under the condition of continuous drought, the seedling height, ground diameter, root length, root thickness, lateral root length, lateral root number, and root volume of the strain were significantly higher than those of the control, and the seedling biomass and nutrient(N, P, K) contents all increased at first, and then decreased, and reached the maximum value of stress on the 21 st day;among the five mycorrhizal seedlings, the effect of inoculating S.luteus 1 was the best.Compared with CK, the seedling height and ground diameter increased by 37.8% and 36.5%, the biomass increased by 48.3%, the root length, root thickness, lateral root length, lateral root number and root volume increased by 67%, 45%, 204%, 122%, 450%, respectively, and the contents of N, P, and K increased by 129%, 111%, 212%, respectively.The recovery ability of mycorrhizal seedlings after rewatering was significantly higher than that of CK.Rewatering after mild to moderate drought stress(14-21 d) was beneficial to the growth and development of the root system of mycorrhizal seedlings, and severe drought stress(28-35 d) caused certain damage to the seedlings of P.massoniana Lamb., and it was difficult to recover after rehydration;after rehydration, S.luteus 1 significantly promoted the growth of the root length and the number of lateral roots of the seedlings, and reached the maximum after 14 days of stress, with an increase of 59.6%., 23.5%.There was a significant positive correlation between the biomass and P content of seedlings after continuous drought and rehydration.The biomass of masson pine mycorrhizal seedlings after inoculation with P.tinctorius was significantly positively correlated with root length and lateral root length >5 cm.【Conclusion】Ectomycorrhizal fungi increases the biomass of seedlings, promote root growth and nutrient absorption, and increases the stress resistance of seedlings after continuous drought and rehydration.Mycorrhizal seedlings by inoculating S.luteus 1 should be selected in mildly arid regions, which could improve the survival rate of afforestation and increase the adaptability of seedlings to drought.