Terrestrial arthropods broadly possess endogenous phytohormones auxin and cytokinins

Abstract

Some herbivorous insects possess the ability to synthesize phytohormones and are considered to use them for manipulating their host plants, but how these insects acquired the ability remains unclear. We investigated endogenous levels of auxin (IAA) and cytokinins (iP and tZ), including their ribosides (iPR and tZR), in various terrestrial arthropod taxa. Surprisingly, IAA was detected in all arthropods analysed. In contrast, tZ and/or tZR was detected only in some taxa. Endogenous levels of IAA were not significantly different among groups with different feeding habits, but gall inducers possessed significantly higher levels of iPR, tZ and tZR. Ancestral state reconstruction of the ability to synthesize tZ and tZR revealed that the trait has only been acquired in taxa containing gall inducers. Our results strongly suggest critical role of the cytokinin synthetic ability in the evolution of gall-inducing habit and IAA has some function in arthropods.

Short‐Range Atomic Topology of Ab Initio Generated Amorphous PdSi Alloys

“…The first peak is due to the Pd-Si partial and is located at 2.43 Å for c = 22% and decreases down to 2.39 Å for c = 2.5% as the Si concentration decreases, as can be seen in Figure 2c. Fukunaga and Suzuki reported 2.42 Å for c = 22%, [12] very close to our results. The second peak of the first coordination shell is due to the partial Pd-Pd, which can be seen in Figure 2b, this peak is located at 2.77 Å for c = 22% and decreases as the Si concentration decreases, to 2.69 Å for pure palladium; Fukunaga and Suzuki reported 2.78 Å for c = 22%.…”

“…The second coordination shell is located between 4.2 and 5.7 Å and is composed of two main peaks [3] with some reminiscence of multiple secondary peaks, as can be seen in the RDF of Figure 3a; this complex second coordination shell was first reported by Fukunaga and Suzuki [12] and has been confirmed by other authors. [19,20] The partial Pd-Pd is the dominant factor in the bimodality of the second coordination shell; this bimodality is characteristic of all amorphous metals.…”

“…The agreement with Fukunaga and Suzuki is remarkable for Pd 78 Si 22 , Figure 1a; for Pd 80 Si 20 , Figure 1b, and for Pd 85 Si 15 , Figure 1d. [12] There is a very good agreement for the first peak of the Pd-Pd partial PDF, pPDF, for the Pd 85 Si 15 with Andonov [13] but there seems to be some discrepancy in the first peak of the Pd-Si pPDF, since Andonov report a peak below 2 Å as can be seen in Figure 1c. Meanwhile, the Pd─Si bond length reported in the literature varies from 2.26 to 2.45 Å, [14] in agreement with this work's results of 2.41 Å, on average, for the Pd─Si bond length, as seen in Table 1.…”

“…The second peak of the first coordination shell is due to the partial Pd-Pd, which can be seen in Figure 2b, this peak is located at 2.77 Å for c = 22% and decreases as the Si concentration decreases, to 2.69 Å for pure palladium; Fukunaga and Suzuki reported 2.78 Å for c = 22%. [12] There seems to be an absence of first neighbors in the Si-Si partial as can be seen in Figure 2d, the first visible peak in the Si-Si partial is located around 3.9 Å, a second neighbor interaction because the Si─Si bond length is 2.36 Å for the crystalline solid.…”

“…[7], one must assume this accomplishment with care since the overall shape of this distribution function seems to resemble that of a liquid more than that of an amorphous. The synthesizing path is interesting and may eventually lead to creating a sample of a-Pd [12] b) Pd 80 Si 20 PDF versus Fukunaga and Suzuki [12] and Masumoto as reported by Waseda, [12,18] c) Pd 82.5 Si 17.5 PDF versus Andonov, [13] d) Pd 85 Si 15 PDF versus Fukunaga and Suzuki, [12] e) Pd 80 Si 20 rPDF versus Mrafko and Duhaj, [15] f) Pd 78 Si 22 RDF versus Crewdson. [16] The insets show the second coordination shell.…”