Allelopathic Effect Of Masson Pine(Pinus Massoniana Lamb.) And Chinese Fir (Cunninghamia Lanceolata (Lamb.) Hook.) On Target Plants

Allelopathy is a common phenomenon in nature, it refers to plants have positive or negative impact on growth of the nearby plants (including micoorgansms) through release allelochemicals to environment.Use of plant allelopathy replacing part of chemical herbicides, or through clarifing allelopathy mecanism to overcome auto-toxicity induced by continuous cropping, therefore, allelopathy research has always been a hot research topic.Masson pine (Pinus massonian Lamb.) and Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) are important tree species, and have important values of forest ecosystem, but both species suffer in growth disorder due to litter and other self-poisoning. Allelopathy effects on both tree roots have been reported, but allelopathy research of important plants generating auto-toxicity rarely reported.In order to evaluate allelopathic potential of Masson pine and Chinese fir's fresh leaves and litter to target plants, such as rice, lettuce and radish, the agar biological detection was revised and employed. To find out possible allelopathic substance in Masson pine and Chinese fir, GC-MS detection method was employed for this purpose, and through component classification to elaborate allelopathic mechanisms of Masson pine and Chinese fir.1. The allelopathy of Masson pine and Chinese fir to rice is facilitated in low concentration, inhibited in high concentration, while lettuce and radish were inhibited, and strengthening with the increasing concentration.To explore the allelopathy of masson pine and Chinese fir, we study the effect of the Masson pine fresh leaves, Masson pine litter leaves, Chinese fir fresh leaves, Chinese fir litter leaf with different concentration (0.5g/1,1.0g/1,1.5g/1) on the germination, radicle length, hypocotyl length, root length, seedling height, root, weight, seedling weight, chlorophyll content and protein content of rice, lettuce and radish. Using agar mix powder method, the bioassay tests were carried out in the artificial climate box. The results showed that, compared with the control group, the leaf powder of four materials in the low concentration could promote rice radicle length, hypocotyl length, and root length, but all were inhibited in high concentration. Further, Masson pine and Chinese fir leaf have inhibition on seedling germination and growth parameters, and with the concentration increasing, the inhibition enhanced.2. Target plants'chlorophyll and protein content reduce with the concentration of Masson pine and Chinese fir increasing.Nurture rice, lettuce and radish in artificial climate box for 7 days, take the leaf in the mixture of acetone:ethano 1=2:1 for 24h, extracts were detected absorbance at 663 nm and 645 nm conditions, and then calculate the chlorophyll content. Protein content by Coomassie brilliant blue method were determined. Experimental results showed that, Masson pine and Chinese fir leaves have inhibited the chlorophyll and protein content of three target plants, and inhibition enhanced with the increasing concentration of leaf powder.3. Detect substance of GC-MS analysis of Masson pine and Chinese fir leaf aqueous extraction mainly dominated by hydrocarbons and acids.Extracted the water extration liguid of the four materials with ether, and evaporated with rotary evaporator in 4?, dissolved with lml ether, dectect by GC-MS. The results showed, pine fresh leaves, litter leaf, fir fresh leaves, litter leaf have been identified 114,98,95,102 chemical substances respectively, meanwhile,44,48,36,35 of compounds evaluated with relative contents are more than 0.6%. Those organic compounds contain hydrocarbons, alcohols, acids, aldehydes, ketones, phenols and esters, among which each extracts organic acids, constitute the largest share.4. Allelochemicals analysis of Masson pine and Chinese firChemical components of Masson pine and Chinese fir detected through GC-MS were checked by standard library and allelopathic substances were acquired. Masson pine fresh leaves chemicals including:phenol,4-hydroxy-benzaldehyde, vanillin, benzenecarboxylicacid, 1,2-benzenedicarboxylicacid,2(4H)-benzofuranone,5,6,7,7a-tetrahydro-4,4,7a-trimethyl-, etc. Wherein the phenolic acids and benzofuranone have allelopathic properties. Masson pine litter chemicals including:butanoic acid,4-hydroxy-benzaldehyde, vanillin,1,2-benzenedicarboxylic acid,3-hydroxy-4-methoxybenzoic acid,2,4,5-trimethoxy-benzaldehyde, 3-ethoxy-4-methoxybenzaldehyde,2,4-dihydroxy-benzaldehyde, epoxy-.alpha.-terpenyl acetate, ect.Chemicals detected in Chinese fir fresh leaves include:4-hydroxy-benzaldehyde, 9-undecenal,3-hydroxy-4-methoxy-benzaldehyde, benzoic acid, n-hexadecanoic acid, octadecanoic acid etc. Most of these materials have allelopathic traits. Chemicals detected in Chinese fir litter include: vanillin,2,4,5-trimethoxy-benzaldehyde, 3-hydroxy-4-methoxy-benzaldehyde,3-hydroxy-4-methoxybenzoic acid, n-hexadecanoic acid, octadecanoic acid,1-methyl-naphthalene, M4-octyne, etc.Compared with litter leaf, the coumarins were the special substances of fresh leaf, and anilines were only detected in Chinese fir fresh leaves. Compared with fresh leaf, the special substances of litter leaf were polyacetylenes and unsaturated esters were only detected in Masson pine litter.