*3.8. Chlorophyll a Fluorescence Determination in Intact L. Perenne Leaves and Dry Biomass Determination*

Chl *a* fluorescence was measured in leaves from the control plants and those treated with alkaloids **1**–**8** at 150 and 300 μM. After 24, 48, and 72 h of spraying, the leaves that adapted to the dark for 15 min were excited by light from an array of 3 light-emitting diodes delivering 3000 μmol m−<sup>2</sup> s−<sup>1</sup> of red light (650 nm). The Chl *a* fluorescence induction curves were measured at room temperature with a portable Hansatech Fluorescence Handy PEA apparatus. Photosynthetic parameters like as PI*abs*, dV/dt0, Sm, ABS/RC, TR0/RC, ET0/RC, TR0/ABS, ET0/TR0, ET0/ABS, PHI(D0), ABS/CS0, TR0/CS0, ET0/CS0, *k*p, *k*n, and Sum*k* were represented in a radar plot [12]. For the dry-biomass experiment, 15 days old *L. perenne* plants treated with alkaloids **1**–**8** at 150 and 300 μM were dried in an oven at 65 ◦C to reach a constant weight. Then, the dry biomass was measured using analytical balance [12].

**Author Contributions:** Conceptualization, T.A.M.V., B.L.-H. and O.M.S.; Methodology, B.S.B., O.M.S. and B.K.-D.; Software, L.C.C.V.; Validation, O.M.S. and B.K.-D.; Formal Analysis, B.S.B., O.M.S., T.A.M.V. and B.K.-D.; Investigation, O.M.S.; Resources, M.F.d.G.F.d.S. and B.L.-H.; Data Curation, O.M.S., T.A.M.V., L.C.C.V. and B.K.-D.; Writing-Original Draft Preparation, O.M.S.; Writing-Review and Editing, O.M.S., T.A.M.V. and L.C.C.V.; Visualization, O.M.S., T.A.M.V. and L.C.C.V.; Supervision, T.A.M.V., B.L.-H. and M.F.d.G.F.d.S.; Project Administration, B.L.-H. and M.F.d.G.F.d.S.; Funding Acquisition, B.L.-H. and M.F.d.G.F.d.S.

**Funding:** The authors gratefully acknowledge financial support from Grants DGAPA-UNAM, IN 205806; CNPq, and CAPES—Finance Code 001.

**Acknowledgments:** Olívia Moreira Sampaio thanks FAPESP (Fundação de Amparo a Pesquisa do Estado de São Paulo-Brazil) for the scholarship support.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### *Molecules* **2018**, *23*, 2693
