Effects Of Exogenous Mineral Elements On Rosa Hybrida And Macrosiphum Rosirvorum Zhang

Macrosiphum rosivorum Zhang is one of the most harmful insects for thecultivation of Rosa hybrida. The herbivore induced volatiles and the nutrients in Rosahybrida indicate the accurate location of the host plant and also provide the nutrient sourcefor the growth and reproduction for Macrosiphum rosivorum Zhang. The irrigating of themineral elements on plants can change the contents of the volatiles and the nutrients. But,whether the mineral elements can affect the spread, growth and reproduction ofMacrosiphum rosivorum Zhang and what is the mechanism remain unclear up to now. Theeffects of exogenous mineral elements on Rosa hybrida and Macrosiphum rosirvorumZhang has been explored in the present study, aiming to provide some fundamentalinformation for the green prevention of the Macrosiphum rosirvorum Zhang. The mainresults and conclusions were drawn as following:(1)The solutions prepared with five elements, including K, Ca, Fe, Si and Mn, wereirrigated on the plants for20days. The results show that the elements with differentconcentrations promote the growth of the plants (P<0.05). Among the irrigated elements, Kand Ca appear to have the most significant effects. The net growths of the plants irrigatedwith the two elements are2～3times as the reference groups. In contrast, the net growthsof the plants irrigated with Fe and Si are relatively lower, about two times as the referencegroups. Mn has the weakest effect. Except the group irrigated with0.05%K, the contents ofchlorophyll for other group are lower than that of the reference group and the difference issignificant (P<0.05).(2)It was found that the Rosa hybrida which were irrigated with the above mineralEspecially for Fe, Si and Mn, the corresponding contents of soluble sugars are13.2,10.1and17.2mg/g higher than of the reference group on average, respectively. The contents ofthe soluble proteins appear to be significantly different (P<0.05) in the plants irrigated withdifferent elements in different concentrations.(3)It was found that the mineral nutrients were changed after irrigating with differentmineral elements in different concentrations. The plants irrigated with K, Fe, Si and Mnhave higher contents of K, Ca and Mg than the reference groups, while the contents of Pare not significantly different. Significant differences are not observed for the contents of K, P, and Mg between the plants irrigated with Ca and reference groups. In contrast withthe reference group, the plants irrigateed with Fe, Si and Mn have higher contents of Fe,Mn and Zn, whereas the contents of Fe, Mn and Zn in the plants irrigated with K and Caare not significantly changed (P>0.05).(4) Significantly different (P<0.05) reproduction rates are observed in the plantsirrigated with different mineral elements in different concentrations. In the open system,except the groups of0.0005%K and0.0005%Ca which have higher reproduction rates thanthe reference group, the other irrigated groups have lower reproduction rates. Among theirrigated groups, the groups of0.025%Fe and0.025%Si have lower reproduction rates,119.8%and13.0%, respectively,(267.2%for the reference group). Similar results wereobtained in the closed system.(5) The solutions of0.025%Fe and0.025Si were observed to have the effects of bothpromoting the growth of the plants and inhibit the Macrosiphum rosirvorum Zhang. Thenet growths for the two groups are5.5and3cm higher than that of the reference group,respectively, while the reproduction rates are lowered by373.1%and254.2%, respectively.(6) The olfactometer experiments indicate that the probabilities for Macrosiphumrosirvorum Zhang to chose the leaves irrigated with0.5%K、0.05%Ca、0.25%Fe、0.00025%Fe、0.25%Si are higher than that of choosing the reference group. Theprobability of choosing the group of0.025%Fe within30min is34%, lower than thereference group of52%.14%of the insects appear to be not tendentious. The insects whichchose the group of0.025%Si account for38%, also lower than the reference group of46%.For this group,16%of the insects did not exhibit tendency.(7) The GC-MS analysis shows that the chemical composition and the contents of theleaves have been changed after irrigation with Fe and Si. Significantly changes were foundfor alcohols, terpenes, phenols and aldehydes. Forty-one compounds were observed in theirrigated and reference groups. Nine specific compounds were found in the groups of Feand Si, while only two were found in the reference group. Phytols are the chemicals thatare changed most significantly. The contents of the phytols in the Fe-and Si-irrigatedgroups are lower than that of the reference group by141%and58%, respectively. Seven compounds were observed to have the effects on the olfaction response and optionalbehaviors.(8) Scanning using Electro Microscopy on the surface of the leaves shows increasedcompactedness, more horny films, thicker wax coatings, increased densities and length ofdowny and less stomata.Summarizing the above experimental results, it can be found that the irrigation withmineral elements improved the immunity of the Rosa hybrida toward the Macrosiphumrosirvorum Zhang. The effects of mineral elements on the insects mediated by the plantsare related to the metabolism of Rosa hybrida and the changes of the structure of theleaves.