Effect of the Heavy Metals on Developmental Stages of Ovule, Pollen, and Root Proteins in Reseda lutea L. (Resedaceae)

Abstract

Heavy metals are some of the most important environmental pollutants. Excessive amounts of heavy metals adversely affect plant growth and development. Also, the presence of elevated levels of heavy metal ions triggers a wide range of cellular responses including changes in gene expression and synthesis of metal-detoxifying peptides. The overall objective of this research was to elucidate some microscopic effects of heavy metals on the formation, development, and structure of pollen, ovule, and embryo and also root proteins in Reseda lutea L. For this purpose, the vicinity of Ahangaran lead-zinc mine (Hamedan, Iran) was chosen as a polluted area where amount of some heavy metals was several times higher than the natural soils. Flowers and young buds were collected from non-polluted and polluted plants, fixed in FAA(70), and studied during developmental stages by light microscopy. The results showed that heavy metals can cause some abnormalities during the pollen and ovule developmental process. The number of pollen grains was decreased, and their shape was changed. Increasing in thickness of the callosic wall and stabilizing of tapetum layer were observed in polluted plants. Asymmetrical formation of ovular integuments, degradation of egg apparatus, irregular formation of embryo sac, considerable vacuolation of embryonic cells, and degeneration of embryo in the late stage of heart-shaped embryo are the results of heavy metal pollution. For protein studies, young roots were harvested from plants exposed to pollution and non-exposed to pollution at the same time. Root proteins were extracted and studied by electrophoresis. The results revealed that some new proteins were synthesized in polluted samples that probably elevate plant tolerance to heavy metals.

Bioremediation of Heavy Metal Pollution by Nano-Particles of Noaea Mucronata

“…All heavy metals at high concentrations have strong toxic effects and are regarded as environmental pollutants [6,7,8].…”

“…Sawidis [5] showed that heavy metals have toxic effect on the pollen growth and pollen tube growth and cause to be a range of strong morphological abnormalities, characterized by uneven or aberrant growth, including apical branching or swelling at the tip of the pollen tube. Several researchers also showed toxic effects of heavy metals on different organisms [6][7][8].…”

Nickel accumulation in leaves, floral organs and rewards varies by serpentine soil affinity

“…Furthermore, it is unknown whether most serpentine plants accumulate Ni into pollen grains, despite evidence that plants growing in soils contaminated by metals via human activities can accumulate them into pollen (Moroń et al 2012). Metals in pollen could reduce germination (citations above; Mohsenzadeh et al 2011; Yousefi et al 2011 a ) or pollinator attraction (Meindl and Ashman 2014), and Ni accumulation in nectar can affect pollinator foraging (Meindl and Ashman 2013, 2014). Thus, a first and necessary step towards understanding the reproductive consequences of growth on serpentine soil is documenting metal concentrations of reproductive organs and floral rewards of non-hyperaccumulating serpentine plants, as well as determining whether or not non-hyperaccumulating endemic species are better able to avoid potentially deleterious effects of metals by excluding them from reproductive organs than non-endemics.…”

Effect of Shoot Cutting on Trace Metal Concentration in Leaves and Capitula of Potential Phytoaccumulator, Invasive Erigeron annuus (Asteraceae)

“…We were also intrigued how metals are distributed between plant vegetative and generative organs. Mohsenzadeh et al (2011) showed that the excessive amounts of heavy metals negatively affect plant growth and development, including the development of the ovules and embryos. Musielińska et al (2016) showed the lower concentration of zinc in flowers than in leaves of the closely related E. ramosus (Walters) Britton, Sterns & Poggenb., as well as in many other species from the family of Asteraceae.…”