Screening Of Saline/Alkaline-Tolerant Ectomycorrhizal Fungi Strains And The Study Of Ectomycorrhizal Synthesis,Saline/Alkaline-Tolerance Of Pinus Thunbergii Parl. Seedlings

Pinus thunbergii Parl. is a pioneer specie in the construction of temperate coastal shelterbelt, and it was used in biorestoration of saline/alkaline areas and was introduced from Japan. It is an important measure to improve the salinity tolerance and afforestation of Pinus thunbergii Parl. in saline soils by using the ectomycorrhizal Pinus thunbergii Parl.. However, less attention was paied in the study of synthesis of the Pinus thunbergii Parl. ectomycorrhizas. In this paper,18of mycorrhizal fungi strains were used to compare their saline/alkaline-tolerance; the synthetic substrate of black pine mycorrhizal seedlings was optimized; and14of ectomycorrhizal pine seedlings were successfully synthesized. The physiological responses of ectomycorrhizal pine seedlings on saline stress were also studied, the results are as follows:1, A total of18ectomycorrhizal fungi strains was used in this study, including Cenococcum geophilum, No.CG, Lactarius hatsudake, No.LH, Laccaria amethystea, No.LA, Pisolithus tinctorius, No.PT, Rhizopogon superiorensis, No.RS, Scleroderma areolatum, No.SA, Suillus luteus:the two strains was No.SL1and SL2, Hysterangium sp., No.U14, Ileodictyon gracile, No.U15, Melanogaster intermedius, No.MI, and9unidentified strains signed UJ, U1, U9, U10, U11, respectively. Only CG has both salt and alkali resistance among the tested strains. CG, LAC, U10, UJ, MI, SL2, U9, U1, RS, SA, LAJ can tolerate salt stress. Based on their relative growth rate, their ability to salt stress is CG, LAC> U10> UJ "MI, SL2, U9> U1, RS, SA "LAJ (""》" indicates P<0.05condition was significantly greater than the right to the left,">" indicates P<0.05greater than the right to the left under the conditions but the difference was not significant, hereinafter the same). MI, U14, CG, SL2, LAJ, LH, UJ, U9strain have the alkali stress capacity (MI、 U14》 CG》 SL2、LAJ、LH》 UJ》 U9). 2, By screening of26different substrates in laboratory conditions, volcanic ash is the most suitable substrates used for inoculation, and its physical and chemical properties as: pH:5.7-6.5, EC:0.02-0.03dS·m-1, bulk density:0.28-0.54kg/m3, water holding capacity:190.13%-304.74%, total porosity:72.30%-107.69%, gas-water ratio:0.27-1.40.3, A total of14ectomycorrhizal seedlings were successfully synthesized using the optimized synthetic substrate. The infection time was within two months, and the infection rate can reach60%or more, except15.4%of the SL1-mycorrhizal seedlings. In addition to CG, LA, RS, SL1, SL2, the remaining strains have not been found in the field survey symbiosis with black pine, and it is the first time to obtained synthetic mycorrhizal seedlings under laboratory conditions. Compared with non-inoculation, the ectomycorrhizal fungi have significant growth-promoting effect of the host plant in the biomass, diameter, plant height, stem length, root length. For example, the biomass of mycorrhizal seedlings infected by PT, U9, LAJ, TM, LAC, SL1, Ull, RS, CG, U10, UZ was significantly (p <0.05) increased of20.5%,30.1%,34.4%,45.1%,51.9%,60.3%,66.1%,94.7%,126.9%,241.2%, respectively, compared with the control seedlings. Root space absorption area was greatly increased in mycorrhizal seedlings. There are different or similar features in the ectomycorrhizal shapes, mycelium color, the amount of lateral roots and root hairs, as well as the morphology of mycorrhizal root tips..4, Soil pot experiment was arranged to study the physiological responses of LAJ-, PT-, CG-mycorrhizal pine seedlings to saline/alkaline stress. The results showed that there was no apparent toxic effects of salt stress in CG-, LAJ-mycorrhizal seedlings two months after soil culture, while PT-mycorrhizal and non-mycorrhizal seedlings showed leaf chlorosis, even death phenomena. Compared with non-mycorrhizal seedlings, chlorophyll a and chlorophyll b and carotenoid content of mycorrhizal seedlings was significantly higher than those of non-mycorrhizal seedlings. The ratio of K/Na in roots were significantly increased in mycorrhizal seedlings. Among three fungi species, CG, LAJ led higher chlorophyll a, b content and proline levels in host plants compare with PT (P<0.05). The results showed that LAJ-and PT-mycorrhizal seedlings had a certain salinity tolerance capacity, and could be used in the afforestation of coastal saline soils.