Comparative analysis of the anatomy of two populations of red-root amaranth (Amaranthus retroflexus L.)

Abstract

The anatomy of stems and leaves of two populations of the weed species Amaranthus retroflexus L. (red-root amaranth) (pop. AMARE1 having green stems covered in sparse hairs and pop. AMARE2 with green but notably dense stem hairs) was analysed in order better to understand the uptake and translocation of herbicides that could be indicative of the species' evolving resistance to herbicides. Samples of the two populations (AMARE1 and AMARE2) were collected from arable land of the Institute of Maize Research at Zemun Polje in 2006. Sampling was performed at the stage of full vegetative growth of plants. Permanent microscoping preparations were made to measure and analyze elements of the anatomy of stems (stem epidermis, cortex, collenchyma, central cylinder and diameter) and leaves (leaf epidermis upper surface and underside, mesophyll, leaf thickness and bundle sheath thickness). Both analysed populations of A. retroflexus, morphologically characterized by different density of stem hairiness, were found to have a typical structure of herbaceous dicots. The stem had three distinctive zones: epidermis, cortex and central cylinder. Amaranth leaves have dorsoventral structure, i.e. their upper surface and underside can be differentiated. The results indicated high and very high significance of differences found in stem anatomy between the two analysed populations, while leaf anatomy was not found to display significant differences other than in mesophyll thickness.

U ovom radu je proučavana anatomska građa stabla i lista dve populacije korovske vrste Amaranthus retroflexus L. (štir) (pop. AMARE1 sa zelenim stablom prepokrivenim retkim dlakama, i pop. AMARE2 takođe sa zelenim ali izrazito maljavim stablom) u cilju boljeg razumevanja usvajanja i translokacije herbicida što može biti u vezi sa odgovorima na razvoj rezistetnosti ove vrste na herbicide. Za ispitivanje anatomske građe stabla i lista ove dve populacije (AMARE1 i AMARE2) uzorci su sakupljeni sa proizvodnih površina Instituta za kukuruz Zemun Polje tokom 2006. godine. Uzorkovanje materijala je rađeno u fazi punog vegetativnog porasta biljaka. Pravljeni su trajni mikroskopski preparati na kojima su mereni i analizirani elementi anatomske građe stabla (epidermis stabla, primarna kora stabla, kolenhim, centralni cilindar i prečnik stabla) i anatomske građe lista (epidermis lica i naličja lista, mezofil, debljina lista i debljina ćelija omotača provodnog snopića). Kod obe analizirane populacije A. retroflexus, koje su se morfološki razlikovale po maljavosti (AMARE1 pop. je zelenog stabla prepokrivenog retkim dlakama, a AMARE2 pop. je takođe zelenog stabla sa izraženom maljavošću), konstatovano je da imaju tipičnu građu zeljastih dikotila. Dakle, stablo ima jasno izdiferencirane tri zone: epidermis stabla, primarnu koru i centralni cilindar. List štira je dorzoventralne građe, što znači da se razlikuje epidermis lica i naličje lista. Dobijeni rezultati ukazuju da se građa stabla dve ispitivane populacije štira statistički značajno ili veoma značajano razlikuje u odnosu na sve analizirane parametre, dok na nivou anatomske građe lista nisu konstatovane značajne razlike, sem u debljini mezofila.