Sampling method of flower-visiting insect community that sampling of flower-visiting insects which are frequently active in Prunus persica flower were done every 5 – 7 days, from 9:00 to 17:00 on April to June 2016 when 5 trees from sunny and shady slope each site, respectively. Photos were taken for insects visiting and foraging nectar and pollen from 3 fixed flower sprays/tree, recording worm access if insects flew away and visited again. Wu , Xue and Zhao and other taxonomic books were consulted for identifying insect species .We detected 20 VOCs emitted from Prunus persica floral branches by ATD-GC/MS, and floral VOCs from sunny slope were more than shady site . On high altitude trees, foral scents from upslope branch are lower than that from downslope of same tree, in accordance with high altitude tree emitted 10 and 15 VOCs from upslope and downslope branches in sunny site, 7 and 8 VOCs from upslope and downslope in shady site. That 6 special floral scents from sunny slope are alpha-dimethyl-benzenemethanol, isoropyl palmitate, ethylbenzene, p-xylene, acetophenone, 3-ethyl-2-methyle-heptane, and 3 special floral scents from shady site are propylene glycol, decanal, hexadecane. Sampled trees from high altitude emit special floral scents are more than low altitude tree, and downslope branches emit special floral scents are more than upslope branches from the same tree except the downslope branches without special scents. Toluene, hexanal, 2-ethyl-hexanol, dodecane, pentadecane 5 VOCs from Prunus persica floral branches can sampled during 8 temporal quantum, that 1 alcohol, 1 aldehydes, 1 terpene, and 2 hydrocarbons common VOCs emitted from sampled floral branches. The highest pentadecane content emitted from upslope branches on low altitude shady slope during 12:37-12:47, the lowest during 10:39-10:49 . VOCs pentadecane, toluene, 2-ethyl-1-hexanol, hexanal emitted 2 climaxes, while docecane emitted 3 climaxes. Floral VOCs emitted from floral branches of Prunus persica differently between temporal dynamic sampled trees, the most VOCs 16 constituents emitted from branches of flower during 10:39-11:08, and the lest floral volatiles 8 constituents emitted on the period 11:20-11:47, 12:00-12:24, 12:37-13:01.
In addition, 6 common floral scents 2-ethyl-1-hexanol, hexanal, toluene, dodecane, tetradecane,pentadecane released from trees during 4 temporal quantum . LSD analysis indicated that 2-ethyl-1-hexanal, dodecane and tetradecane emitted same content all the temporal quantum, while hexanal, toluene and pentadecane emitted different content some temporal quantum. Floral scents from floral branches of high altitude tree in sunny site are significantly with scents from other kind of trees.Insects visit 15 and 4 floral branches of Prunus persica in sunny and shady site, vertical farming racks respectively. Most richness, abundance and diversity on sunny or shay slope is similar, while there is difference between SUSD with n/2 − 1 and n/2 + 1 . Table 4 indicated that floral scent constituent number from sunny slope were significantly negative, and volatile constituent number were remarkably positive correlated with richness, abundance and diversity that insects visiting flowers on sunny or shady slope. Toluene, dodecane were dramatically negative, while tetradecane and pentadecane were significantly positive with SUSR, SUSA, SUSD, SHSR, SHSA and SHSD that FSNS seperated with n/2 − 1 or n/2 + 1, and FSAS with n/2. Floral scents correlated with insect community on sample day, insects only visited Prunus persica flower on shady slope . If floral scents from sunny slope were significantly negative correlated with richness, abundance and diversity, while floral scents from shady slope were remarkably positive correlated with those insect community parameters in shady site. 2-ethyl-1-hexanol, tetradecane and pentadecane were significantly positive, while hexanal, toluene, dodecane are dramatically negative correlated with SHSR, SHSA and SHSD separated FSNS with n/2. After sampled floral scents day that insects visiting Prunus persica floral branches community index that SUSR response to floral scents correlation with n/2 − 1 separated branches is similar to that with n/2 + 1, the same occurred at SHSR response to floral scents . Moreover, there is difference between SUSA that separated branches with n/2 − 1 and n/2 + 1, and SHSA, SUSD, SHSD holding the difference. Table 8 indicated that flower-visiting insect SHSA with n/2 − 1 separated floral branches and SUSA with n/2 + 1 were not correlated with scents from flowers. Floral VOCs and 2-ethyl-1-hexanol from sunny slope were significantly positive correlated with flower-visiting insect community index richness, abundance and diversity on sunny slope, but those scents from shady site were negative correlated with those indexes in sunny and shady sites with n/2 + 1, respectively. Hexanal, toluene, dodecane was evidently negative, while tetradecane, pentadecane was positive with SUSR, SUSA, SUSD, SHSR, SHSD with n/2 − 1. Furthermore, tetradecane, pentadecane was negative, and hexanal, toluene, dodecane was positive with community indexes with n/2 + 1 separated floral branches.
Our results show that 20 floral scents were emitted from 1 variety Prunus persica branches of flower; that is similar to that 22 constituents produced by 1 variety Hydrocleys marii and 13 constituents produced by 1 variety H. nymphoides, while 6 floral VOCs were emitted from 6 varieties of Camellia sinensis, so Prunus persica flower emitted more VOCs than some plants. Floral scents that were released from sunny slope were more than shady slope, dependingon strong sunshine, high temperature, and big humidity affecting floral volatile constituents emitted, which testified different chemical substances of fragrance released from Yucca filamentosa on different slopes’ geography condition. Moreover, floral volatile constituents of high altitude were more than low altitude that strong sunshine on high altitude promotes flowers emitting floral scents on the same slope, and volatiles fromOcimum basilicum leaves on high altitude are lower than low altitude in College of Horticulture and Landscape Architecture of Hainan University. Floral scents of 3-methyl-butanal, hexanal were released from Prunus persica floral branches that were emitted from plant leaves defending pests from foraging. We inferred that once insects visit flowers, floral aldehydes were released from Prunus persica, or volatile constituents were released from leaves, when depending on flower and leaf nutrition substance N, P, K, Ca, Mg, Fe, Mn, Zn, Na and Cu, which affected fruit. Floral aldehydes were emitted from Prunus persica branches on sunny slope emitted with sunshine. Hydrocarbons such as 3-ethyl-2-methyl-heptane, dodecane, tridecane, tetradecane, pentadecane and hexadecane were released from Prunus persica branches, and hydrocarbons produce a pleasant smell, so 6 floral hydrocarbons from Prunus persica attracted insects visiting. Dissimilarity with ATD-GC/MS analysed dominant volatile constituents from Agiceras comiculatum terpenes with poison, and dissimilarity with floral volatiles from Osmanthus fragrans ketones and alcohols. Floral VOCs were differently emitted from Prunus persica on temporal quantum, and difference VOCs of flower were released from Sorbaria kirilowii on different seasons with TCT-GC/MS analysis, while floral scents were produced from Lilium brownii on open period, semi-open, blooming period and recession period, but VOCs were emitted from Rosa rugosa and Sorbaria kirilowii with diurnal rhythm variation. Most floral scents of 16 constituents were emitted from Prunus persica on 10:39-11:08, while same 8 constituents were released from trees on other temporal quanta, which is related with sunshine and temperature, and flower quantity affected volatiles release, different floral volatiles from Agiceras comiculatum branches without flower, with flower and with fruit.
Floral VOCs from Prunus persica before 12:00 are higher than those after 12:00; special floral scents were emitted from both temporal quanta, while floral terpenes and esters were emitted most from Arabian jasmine florescence. Floral hexanal was released in all the sampling time and content from Prunus persica is significantly highest during 10:30-11:30, while hexanal was released from Sorbaria kirilowii in all the sampling time. Pink flowers from Prunus persica and white flowers from Sorbaria kirilowii absorb and reflect different wavelength of light, which release a different amount of hexanal, and flower color has the characteristics of adaptive environment. LSD analysis indicated that there was significantly same floral scent dynamic difference of some constituents, same floral volatile constituents emitted different contents from Sorbaria kirilowii during 7:00-19:00, and same floral scent constituents emitted different contents from Rosa rugosa one day. There was same floral volatile significant difference of common constituents among some temporal quantum, while VOCs were emitted significant difference from Sorbaria kiriowii on different temporal quanta one day, and floral scents were differently released from Lilium brownii on different period.Floral scent correlation with insect community that floral VOCs emission responded to insects visiting Prunus persica flower branches and floral VOCs total content and relative content of each component response to Mylabris forage. Methyl benzenecarboxylate emitted from pollinated Pentunia flower with certain rules , while more volatiles released from the plant that foraged by insects to attract enemy insects, and volatile emission correlated with foraging insect population. Flavoring substance VOCs emission from Cirsium flowers increased with flower-visiting insect community index ascend , while VOCs emitted from needles correlated with Dendrolimus punctatus burst frequently, furthermore, fragrance floral VOCs emitted from Heterobathmiina pollinated flowers are higher than that Aves pollinated flowers. We first founded that there were different correlation between floral scents and insect community visited Prunus persica floral branches before sampled day, that odd branch number from sunny slope and even branches from shady slope separated with n/2 − 1 or n/2 + 1, and n/2, but the floral scent constituents is negative correlated with flower-visiting insect community richness, abundance and diversity on the sunny slope, and positive correlated with those indexes adopted whichever separated method, so could adopted some floral scents that positive correlated with flower-visiting insects on sunny slope to attract insects pollinating. We firstly inferred that floral scents response to flower-visiting insect community depending on the tree branch number and even branches distributed slopes, because 2-ethy-l-hexanal, toluene, dodecane are dramatically negative, while tetradecane and pentadecane are significantly positive with SUSR, SUSA, SUSD, SHSR, SHSA and SHSD that FSUS separated with n/2 − 1 or n/2 + 1, and FSHS with n/2.
We concluded that 2-ethyl-1-hexanol from sunny and shady slope could be used to attract insects visiting flower of Prunus persica, in that insects only visiting floral branches on shady slope that holding odd floral branches, and 2-ethyl-1-hexanol from sunny and shady slope were positive correlated with SHSR, SHSA and SHSD on sampled volatiles day. But, after sampled volatiles day floral scent constituents and 2-ethyl-1-hexanol on sunny slope were positive correlated with SUSR, SUSA, SUSD, and negative correlated with SHSR and SHSD, vertical rack system that separated floral branches with n/2 − 1. So 2-methyl-1-Hexanol from sunny and shady slope could used to lure insects to pollinate on separate slopes, just as flora scents from one kind of plant attract insects pollinating. While no quantitative insects visiting floral branches of Prunus persica that disadvantage sunshine and temperature climate condition on shady slope, and once insects visit floral branches, volatile constituents and quantity emitted possibly from Prunus persica to attract insects visiting to pollinate or inhibit insects foraging flowers, so floral scents were significantly related with flower-visiting insect community indexes . Advantage sunshine and temperature climate condition on sunny slope distributed more flower-visiting insect species that pollinated easily. In addition, flower structural characteristics, the amount and composition of nectar affect flower-visiting insect species . When insects visiting, less floral volatile constituents and contents emitted from Prunus persica branches to inhibit insects from visiting, and secondary metabolic substances emitted from Prunus persica branches to inhibit insects from visiting.Punus persica in Wan Bailin Ecological Garden healthily grow and fruit need insect visiting and emitters attract and inhibitory floral scents, we first definite the 20 floral scents, dominant and special fragrance of Prunus persica that which constituents are attractive could be specific to lure insects pollinating in the future, and perhaps that 2-ethyl-1-hexanol is likely to attract insects, mostly. We first presented that floral scents emission correlated with floral branches and hold different response to flower-visiting insect community indexes separated floral branches with even or odd methods, that prune Prunus persica tree leaving branches odd on sunny slope and even on shady slope to promote those tree growing and fruiting, and get high economic benefit.The arboretum section of the Rio de Janeiro’s Botanical Garden comprises about 1500 species and almost 9000 specimens.