Effects of the nanoherbicide made up of atrazine-chitosan on the primary events of photosynthesis

CORDON, GABRIELA; LOPEZ VALIÑO, IVANA; PRIETO, AGUSTINA; COSTA, CECILIA; MARCHI, M. CLAUDIA; DIZ, VIRGINIA

Journal of Photochemistry and Photobiology

Elsevier

Lugar: Amsterdam; Año: 2022 vol. 12

2666-4690

In this research , ch itosa n an d alginate nanoca psule s (NCs ) have been sy nth esize d an d designed to ac t as ca rrier s (controlle d releas e sy stems ) of atrazine mo l ecules. Atrazine is an he rbicide associated with re l atively high chroni c to x i city, whic h ca n also be accumulate d as a reca lcitran t su bstance in su rface an d groundwater. This effect is enhanced by the presence of adjuvants that are part of the commercial formulation. Therefore, the proposal to transport the herbicide in a nontoxic biocompatible nano-encapsulated system is particularly relevant. Th e nano -capsulated sy stems with an d withou t th e inco rporate d he rbicide (NH, nanohe rbicide an d empt y NCs, respectively ) were characte rized by scanning electron microscopy images showin g an averag e nanoca psule size of 35 0 nm an d a pa rticl e co nce ntr ation of 4. 5 × 1013/ml. Th e chem ica l co mposition of th e NC s an d NH sy stems wa s studie d by Fourie r Tran sform Infrared Spectroscopy . Th e OJIP transien t chlorophyl l fl u ore scenc e wa s used to eval uat e th e effect s of th e NH , co mme rcial atrazine (At) an d empt y NC s on maiz e plants as no n -target an d on chicor y as ta rge t plants . Fo r th e chicor y plants treate d with th e NH an d At , a decrease in th e acti vit y of th e ox y - ge n -generating co mplex (F v/F 0 ) an d in th e ma x imu m quantu m yiel d of PSII ( φP0 = TR 0/ABS ) wa s observed . In addition , seriou s alte rations in th e electronic tran sport flux (E T 0/RC) , in th e quantu m yiel d fo r electron tran sport ( φE0 = ET 0/ABS ) an d in th e efficiency or prob abi lit y that an electron move s betwee n plastoquinones Q A an d Q B (E T 0/T R 0 ) were obtained fo r this thes e plants . Th e quantu m yiel d of th e tran sport stream electron s to PS I electron acce ptors ( φR0 = RE 0/ABS ) an d th e efficiency with whic h an excito n will be tran sferred from PSII to PS I acce p - tors ( ψRE = RE 0/T R 0 ) also fell in th e plants spraye d with th e NH or co mme rcial atrazine with respec t to th e co n - trol plants an d thos e treate d with th e empt y NCs. Th e ph otosy nthetic parameters obtained fo r corn plants , treate d with both NH an d co mme rcial atrazine , showed an inhibition of electron tran sport in th e ph otosy nthetic proces s at 24 h. Thes e effect s were reversed afte r seve n days of trea tment , du e to th e abilit y of corn plants to deto xify atrazine . Foliar da mag e wa s observed in chicor y plants treate d with atrazine an d with NH bu t no t co n - cernin g corn plants . Chicor y or corn plants treate d with th e pr opose d ca rrier (NCs ) showed no foliar effects, whic h implie s that th e ca rrier is harmless to th e health of th e plants .