The aim of this experiment was to analyze the leaf volatiles of crabapple ( Malus sp.) individuals at different aphid’s resistance, to ascertain the particular ingredients which has lure or aversion effects on aphid, and to provide reference for finding out a simple method to control effectively aphids. Volatiles of leaves from twenty-one different crabapple individuals were evaluated with the method of head space-solid phase micro-extraction and gas chromatography-mass spectrometry (HS-SPME-GC-MS). Volatiles profiles of them were then compared. There are one hundred eighty-six kinds of volatiles were detected with varied contents found in different individuals. And all plants contain eight kinds of common components: 3-Hexen-1-ol, acetate, (Z)-, 4-Hexen-1-ol, (Z)-, n-Decanal, n-Tetradecane, .alpha.-Farnesene, Diethyl Phthalate, Oxime-, methoxy-phenyl- and Dibenzofuran-, wherein the relative content of higher have 3-Hexen-1-ol, acetate, (Z)- and 4-Hexen-1-ol, (Z)-. Specific volatile substances in high resistance plants contain 3-Hexenal, (Z)- and 2-Hexenal, (E)-. Leaf volatiles differ in twenty-one crabapple individuals. High resistance plants specific volatile substances contains 3-Hexenal, (Z)-, 2-Hexenal, (E)- and other small molecular volatile substances, and no-resistance plants all have .beta.-Farnesene.
Plant volatile organic compounds, which are produced by the metabolism of secondary metabolites, vary be- tween individuals. Factors such as volatiles’ type, quantity and concentration have a lure and aversion to insects and determine feeding direction of some infects. Plant volatile compounds are an important part of plant defense, therefore ascertaining volatiles’ properties and function to phytophagous insects will contribute to put forward a new pest control strategies.
In recent years, the plant volatiles are widely concerned or receive extensive attention in the ecology and phytophagous insects study. Green leaf volatiles, which are produced by biosynthesis, such as leaves alcohol from unsaturated fatty acid, aldehyde and their derivatives, can affect many insect behaviors [
Myzus persicae (Sulzer) is one of the important pests of crabapple blade. Ornamental crabapple has excellent Ornamental value, such as flowers, foliage, fruit and so on and strong adaptability. Therefore it has been widely applied in a variety of landscape. But the leaves are often susceptible to aphids and we have to take chemical meas- ures to prevent and control aphids. There were some individuals that can resistant aphids among half-sib groups we cultivate. Through the study of crabapple blade volatiles, this paper discusses the reason that there are dif- ferent degrees of aphids’ resistance and expects to find new method of prevention and control aphids.
There is a group of seedling obtained by Ralls and crabapple hybrid in 2005. The orchard irrigation condition is good, and the management level is consistent, also the Crabapple growth in good condition. In the growing sea- son of 2012, we found these seedlings showed different resistance to aphid, so we divided these seedlings into three categories (
The experiment was took place in State Key Laboratory for Crop Biology Shandong Agricultural University Tai’an, Shandong in June 2012. Tested materials are showed in
Respectively 5 - 7 crabapple branches were randomly selected around the bough and brought back to the labora- tory. These branches are insert water and different plant is separated to prevent aroma mixed. 7 g clean blades from retrieving branches in the conical flask with aluminium foil seal are adsorbed 40 min at room temperature with the aging extraction head, which are desorbed 2.5 min at 250˚C. And at the same time the GC-MS is launched to gain data.
The gas chromatographic condition: chromatographic column used was RestekRtx-5 ( 30 m × 0.32 mm × 0.25 μm), Splitless injection of 1 μL solution was performed at an injection port temperature of 250˚C. Helium was used as carrier gas at a flow rate of 3 ml∙min−1. The column temperature was maintained at 40˚C for 2 min, then programmed at 7˚C/min to 140˚C, then at 15˚C/min to 250˚C, which was held for 5 min.
The transfer line temperature was 200˚C. The mass spectrometer was operated in electronimpact (EI) ioniza-
Aphid Damage Level | Leaf Damage Degree | Aphids Resistance |
---|---|---|
I level | Rarely aphids harm, no leaf curl phenomenon | High-resistance |
II level | Mild aphids harm, leaf curl less than 50% | Moderate-resistance |
III level | Serious aphids harm, leaf curl more than 50% | No-resistance |
tion mode with electron energy of 70 eV. Scan range was 33 - 450 aMU.
Gas chromatography data processing system, the computer retrieval and NIST library (107 k compounds) and Wiley library (y320 k compounds, version 6.0), combined with the artificial map matching were used to confirm all kinds of chemical composition of volatile substances. According to peak area normalization method for their relative content, only when the matching degree and purity is greater than 80 (maximum 100) identification re- sults will be reported.
Volatiles of leaves from twenty-one different crabapple individuals were evaluated with the method of HS- SPME-GC-MS and search into computer library. There are one hundred eighty-six kinds of volatiles were de- tected with varied contents found in different individuals. And all plants contain a total of eight kinds of common components: 3-Hexen-1-ol, acetate, (Z)-, 4-Hexen-1-ol, (Z)-, n-Decanal, n-Tetradecane, .alpha.-Farnesene, Diethyl Phthalate, Oxime-, methoxy-phenyl- and Dibenzofuran-. Among them, the relative content of most is 3-Hexen-1-ol, acetate, (Z)-, respectively, accounting for the total leaf volatiles of 42.93%, 34.63%, 60.77%, 52.03%, 53.73%, 29.53%, 51.48%, 44.57%, 58.94%, 46.50%, 64.48%, 68.75%, 47.09%, 54.81%, 54.28%, 46.67%, 56.48%, 71.76%, 63.87%, 43.11% and 68.66%. Followed by 4-Hexen-1-ol, (Z)-, accounting for the to- tal leaf volatiles of 31.56%, 24.04%, 14.79%, 15.16%, 26.88%, 28.02%, 14.61%, 18.14%, 21.82%, 24.13%, 12.67%, 14.20%, 16.22%, 21.88%, 21.93%, 15.66%, 20.23%, 15.76%, 16.05%, 26.14 % and 16.46%. The two volatiles play a major role in the formation of leaf aroma and other relative content less volatile may constitute specific aroma between different individual (
No. | 4-Hexen-1-ol, (Z)- | Oxime-, ethoxy -phenyl- | 3-Hexen-1-ol, acetate, (Z)- | n-Decanal | n-Tetradecane | .alpha. -Farnesene | Dibenzofuran | Diethyl Phthalate |
---|---|---|---|---|---|---|---|---|
1 | 31.56 | 0.68 | 42.93 | 0.50 | 0.22 | 1.03 | 0.45 | 1.84 |
2 | 24.04 | 0.65 | 34.63 | 0.33 | 0.15 | 4.52 | 0.26 | 1.18 |
3 | 14.79 | 0.22 | 60.77 | 0.31 | 0.20 | 0.88 | 0.22 | 1.16 |
4 | 15.16 | 4.15 | 52.03 | 0.45 | 0.81 | 2.25 | 0.55 | 7.46 |
5 | 26.88 | 0.51 | 53.73 | 0.38 | 1.65 | 1.49 | 0.26 | 1.30 |
6 | 28.02 | 0.41 | 29.53 | 0.30 | 0.13 | 3.53 | 0.28 | 1.16 |
7 | 14.61 | 0.38 | 51.48 | 0.29 | 0.36 | 0.87 | 0.20 | 0.86 |
8 | 18.14 | 3.45 | 44.57 | 0.16 | 0.29 | 2.49 | 0.29 | 1.02 |
9 | 21.82 | 0.54 | 58.94 | 0.74 | 0.26 | 0.19 | 0.17 | 1.08 |
10 | 24.13 | 0.46 | 46.50 | 0.37 | 0.21 | 1.09 | 0.27 | 1.17 |
11 | 12.67 | 0.22 | 64.48 | 0.26 | 0.10 | 0.21 | 0.13 | 0.55 |
12 | 14.20 | 0.19 | 68.75 | 0.25 | 0.39 | 0.40 | 0.16 | 0.64 |
13 | 16.22 | 0.16 | 47.09 | 0.39 | 0.16 | 0.26 | 0.14 | 0.56 |
14 | 21.88 | 0.21 | 54.81 | 0.25 | 0.19 | 0.21 | 0.22 | 0.91 |
15 | 21.93 | 0.32 | 54.28 | 0.18 | 0.13 | 0.23 | 0.19 | 1.21 |
16 | 15.66 | 0.16 | 46.67 | 0.20 | 0.16 | 2.57 | 0.19 | 0.87 |
17 | 20.23 | 0.18 | 56.48 | 0.51 | 0.11 | 0.63 | 0.19 | 0.85 |
18 | 15.76 | 0.37 | 71.76 | 0.14 | 0.07 | 0.03 | 0.14 | 0.62 |
19 | 16.05 | 0.20 | 63.87 | 0.21 | 0.34 | 0.26 | 0.14 | 0.54 |
20 | 26.14 | 0.27 | 43.11 | 0.39 | 0.40 | 1.35 | 0.17 | 0.80 |
21 | 16.46 | 0.16 | 68.66 | 0.25 | 0.18 | 0.05 | 0.17 | 0.59 |
According to chemical composition, the 186 volatiles can be divided into 45 hydrocarbons, 45 esters, 22 al- cohols, 13 terpenoids, 9 aromatic, 8 aldehydes, 7 ketones, 1 ethers and 1 acids (
VOCs sorts in crabapple individuals of different aphid resistance are different from hydrocarbons, alcohols and aldehydes. For high-resistance, moderate-resistance and no-resistance, ester volatiles account for 58.98%, 68.20% and 71.20%, alcohols for 24.82%, 19.79% and 19.62% and aldehydes for 2.48%, 1.98% and 1.68% of the total volatiles, respectively. The more relative content of esters and aldehydes, and the lower the alcohols, the greater resistance to aphids.
The sort and relative content of the seven individuals of the same resistance is different (
Results showed that crabapple individuals of different aphid resistance have special volatiles in their blades (
Host plant’s VOCs play an important role in the selection process of the host plant in aphids. Plant green leaf volitiles generate aldehydes, alcohols and other small molecule compounds, such as n-hexanol, n-hexanal,
VOCs sorts | Quantity (number) | Relative content (%) |
---|---|---|
Hydrocarbons | 80 | 5.89 |
Esters | 45 | 66.13 |
Alcohols | 22 | 21.41 |
Terpenoids | 13 | 2.08 |
Aromatic | 9 | 0.96 |
Aldehydes | 8 | 2.03 |
Ketones | 7 | 1.36 |
Ethers | 1 | 0.35 |
Acids | 1 | 0.03 |
Total | 186 | 100.00 |
VOCs solts | Resistance to aphids | Total (number) | Relative content (%) | Sample number | Variable coefficient | ||||||
---|---|---|---|---|---|---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 | 7 | |||||
Hydrocarbons | No-resistance | 45 | 6.63 | 14 | 14 | 14 | 12 | 13 | 16 | 13 | 9.14% |
Moderate-resistance | 54 | 5.62 | 19 | 17 | 15 | 11 | 13 | 15 | 11 | 20.74% | |
High-resistance | 47 | 5.43 | 13 | 14 | 15 | 13 | 12 | 14 | 16 | 9.71% | |
Esters | No-resistance | 34 | 58.98 | 8 | 17 | 20 | 6 | 8 | 11 | 18 | 44.96% |
Moderate-resistance | 34 | 68.20 | 6 | 11 | 18 | 16 | 16 | 19 | 17 | 31.32% | |
High-resistance | 36 | 71.20 | 17 | 20 | 16 | 18 | 19 | 18 | 17 | 7.53% | |
Alcohol | No-resistance | 15 | 24.82 | 10 | 6 | 5 | 4 | 5 | 6 | 3 | 39.94% |
Moderate-resistance | 16 | 19.79 | 5 | 7 | 6 | 7 | 6 | 7 | 10 | 22.95% | |
High-resistance | 11 | 19.62 | 7 | 5 | 7 | 6 | 4 | 5 | 5 | 20.35% | |
Terpenoids | N-resistance | 10 | 3.70 | 3 | 7 | 8 | 5 | 5 | 7 | 8 | 30.35% |
Moderate-resistance | 7 | 1.24 | 4 | 4 | 3 | 7 | 4 | 4 | 5 | 28.73% | |
High-resistance | 7 | 1.30 | 4 | 7 | 4 | 3 | 4 | 6 | 4 | 30.57% | |
Aldehydes | No-resistance | 7 | 2.48 | 4 | 4 | 6 | 2 | 4 | 3 | 3 | 33.75% |
Moderate-resistance | 7 | 1.98 | 1 | 5 | 3 | 5 | 4 | 7 | 5 | 44.10% | |
High-resistance | 6 | 1.68 | 2 | 3 | 5 | 4 | 6 | 5 | 5 | 32.20% | |
Aromatic | No-resistance | 7 | 1.48 | 5 | 1 | 2 | 1 | 4 | 2 | 2 | 62.25% |
Moderate-resistance | 7 | 1.00 | 4 | 3 | 2 | 1 | 1 | 1 | 4 | 60.38% | |
High-resistance | 4 | 0.41 | 3 | 2 | 2 | 1 | 3 | 2 | 1 | 40.82% | |
Ketones | No-resistance | 4 | 1.55 | 2 | 1 | 0 | 1 | 1 | 1 | 0 | 80.51% |
Moderate-resistance | 5 | 2.18 | 1 | 3 | 2 | 2 | 3 | 4 | 0 | 62.78% | |
High-resistance | 4 | 0.36 | 3 | 3 | 1 | 1 | 2 | 3 | 2 | 41.99% | |
Acids | No-resistance | 1 | 0.35 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | - |
Moderate-resistance | - | - | 0 | 0 | 0 | 0 | 0 | 0 | 0 | - | |
High-resistance | - | - | 0 | 0 | 0 | 0 | 0 | 0 | 0 | - | |
Ethers | No-resistance | - | - | 0 | 0 | 0 | 0 | 0 | 0 | 0 | - |
Moderate-resistance | 1 | 0.03 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | - | |
High-resistance | - | - | 0 | 0 | 0 | 0 | 0 | 0 | 0 | - | |
Total | No-resistance | 123 | 100 | 46 | 50 | 55 | 31 | 41 | 46 | 47 | 16.75% |
Moderate-resistance | 131 | 100 | 40 | 51 | 49 | 49 | 47 | 57 | 52 | 10.52% | |
High-resistance | 115 | 100 | 49 | 54 | 50 | 46 | 50 | 53 | 50 | 5.23% |
Z-3-Hexenal and so on, under the action of LOX and HPL [
Compounds | Relative Content (%) | ||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Anti-Resistance | Moderate-Resistance | High-Resistance | |||||||||||||||||||
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | |
3-Hexenal, (Z)- | 0.62 | 0.38 | 0.75 | 0.59 | 1.90 | 2.47 | 0.30 | 0.67 | 1.39 | 0.78 | 0.78 | 0.52 | 1.19 | 1.55 | |||||||
2-Hexenal, (E)- | 0.07 | 0.05 | 0.09 | 0.27 | 0.38 | 0.20 | 0.11 | 0.07 | 0.16 | 0.24 | |||||||||||
2-Isopropyl-5- methyl-1- hexanol | 0.03 | 0.03 | 0.03 | 0.05 | 0.02 | ||||||||||||||||
2-Isopropyl-5- methyl- 1-heptanol | 0.03 | 0.03 | 0.02 | 0.02 | 0.05 | 0.01 | 0.03 | 0.03 | |||||||||||||
1,5-Heptadien- 4-one, 3,3,6- trimethyl- | 6.42 | 0.22 | 0.30 | 0.02 | 0.10 | 0.34 | 0.11 | 0.09 | 0.04 | 0.02 | 0.13 | 0.09 | |||||||||
2-Penten-1-ol, acetate, (Z)- | 0.75 | 0.35 | 0.26 | 0.38 | 0.30 | 0.94 | 0.61 | 0.21 | 0.46 | 0.64 | 0.68 | 0.72 | 0.60 | ||||||||
4-Hexen-1-ol, acetate | 0.48 | 1.01 | 0.83 | 0.03 | 0.02 | 0.66 | 0.28 | 0.46 | 0.04 | 0.02 | 0.33 | 0.02 | |||||||||
Propanoic acid, 4-hexen- 1-yl ester | 0.09 | 0.40 | 1.07 | 0.93 | |||||||||||||||||
.beta.- Farnesene | 0.29 | 0.13 | 0.40 | 0.49 | 0.12 | 0.70 | 0.06 | 0.11 |
In all chemical information aphids, the most important one is the alarm pheromone, and almost all aphids are releasing this sesquiterpene component. This alarm pheromone is a very effective chemical signal compounds, and can give a warning to predators. In addition, anti-β-farnesene is the main ingredient [
This paper analyzed VOCs of crabapple (Malus sp.) leaves and compared the difference between different aphids’ resistance. Hydrocarbons, alcohols and esters are the main volatiles. Esters’ relative content is the highest and esters have the main role to the aroma of crabapple blade. The sort of hydrocarbons is the most and hydrocarbons may be the main substances that constitute specific aroma between different individual.
VOCs of crabapple leaf differ from individuals of different aphids’ resistance. Special VOCs in high resis- tance plants contain: 3-Hexenal, (Z)-, 2-Hexenal, (E)-, 2-Isopropyl-5-methyl-1-hexanol, 2-Isopropyl-5-methyl- 1-heptanol, 1,5-Heptadien-4-one,3,3,6-trimethyl-, 2-Penten-1-ol, acetate, (Z)-, 4-Hexen-1-ol, acetate and Pro- panoic acid, 4-hexen-1-yl ester. And no-resistance plants all contain β-Farnesene.