青海云杉不同器官水提物对油松种子萌发和幼苗生长的化感作用

Allelopathic Effects of Aqueous Extracts of Picea crassifolia on Different Organs on Seed Germination and Seedling Growth of Pinus tabuliformis

宁夏罗山国家级自然保护区重要植被类型青海云杉(Picea crassifolia)-油松(Pinus tabuliformis)混交林中青海云杉不同器官水提物及枝叶挥发油对油松种子萌发和幼苗生长的化感作用结果表明:青海云杉的根、枝、叶、果实水提取物及枝叶挥发油都含有化感物质,对油松种子萌发及幼苗生长均有显著影响(p<0.05)。水提物在高浓度时起到抑制作用,低浓度时表现起到促进作用,且低浓度(2mg·mL-1)时的促进作用明显强于高浓度(30mg·mL-1)时的抑制作用。与对照相比,在浓度为2mg·mL-1时,青海云杉果实水提取物对油松种子发芽的促进作用最强,种子发芽率提高了73.68%;青海云杉根水提取物对油松幼苗根长和幼苗鲜重的促进作用最强,其根长和鲜重分别提高了66.12%和163.89%;而对油松幼苗苗高促进作用最强的是其叶水提物,提高了149.39%;在浓度为30mg·mL-1时,除青海云杉根水提物对油松幼苗根长表现出促进作用外(提高6.95%),其他提取物对油松种子萌发及幼苗生长均表现出抑制作用。青海云杉枝叶挥发油对油松种子萌发、幼苗生长均表现为促进作用,尤其对种子萌发具有显著的促进作用,其促进率达64.22%。说明青海云杉和油松混交,可能有利于油松种子萌发及幼苗生长,可为油松混交树种的选择、人工造林、森林培育及健康经营管理提供理论依据。

The allelopathic effects of the extracts from roots, branches, leaves, seeds and volatile oil of Picea crassifolia were studied on the seed germination and seedling growth of Pinus tabuliformis in Picea crassifolia-Pinus tabuliformis mixed forest, an important vegetation type of Ningxia Luoshan State Na- ture Reserve. The results showed that Picea crassifolia had allelochemicals, and all extracts had signifi- cant allelopathic effects on the seed germination and seedling growth （p〈0.05）. Aqueous extracts at high concentration exhibited the promotion effect and aqueous extracts at low concentration exhibited the inhibition effect; the promotion effect of extracts on seedling growth at low concentration （2 mg·mL^-1） was stronger than the inhibition at high concentration （30 mg·mL^-1）. Compared with the control, the aque- ous extracts of fruits exhibited the strongest promotion effect on the seed germination by 73. 68%; the aqueous extracts of roots promoted the seedling root length and shoot fresh weight growth by 66.12% and 163.89%, respectively at 2 mg·mL^-1 concentration; the extracts that exhibited the strongest promotion effect on the seedling length was the aqueous extracts of leaves, improved by 149.39%. On the contrary, all extracts had inhibition effects on the seed germination and the growth of seedlings at 30 mg ~ mL 1 con- centration except that the roots aqueous extracts had promotion effect on the seedling root length of Pinus tabuliformis （improved by 6.95%）. The volatile oil of Picea crassifolia had promotion effect on the seed germination and the growth of seedlings, especially significant promotion effect on the former by 64.22 %. It indicated that mixed planting Picea crassifolia and Pinus tabuliformis could have promotion effect on the seed germination and seedling growth of Pinus tabuliforrnis. The results provided theoretical basis for the mixed tree species selection of Pinus tabuliforrnis artificial afforestation, forest cultivation and health management.