A hydroponic greenhouse study was carried out to evaluate the effects of increasing cadmium (Cd) concentration on plant growth, mineral nutrition and Cd distribution of H-250 sunflower genotype. Exposure to increasing Cd concentrations reduced plant biomass by 40, 34, 47 and 42% of the total, leaves, stem and roots dry weights as compared to the control. Regardless of the treatment most of Cd uptake by the genotype was allocated in the root, followed by leaf and stem. The higher bioconcentration factors values in both above ground and underground plant tissues and low transfer factor value indicated that this genotype may be an alternative for use in phytostabilization programs. The results also showed that increasing Cd concentration disrupted plant homeostasis as it increased the concentration of some nutrients and had adverse effect on others, impacting plant growth. In this context, the results suggest that the low magnesium, iron and manganese concentrations in the leaves were the main cause for plant biomass reduction and leaf chlorosis and necrosis, as each one of these elements plays a key role on the chlorophyll molecule and on photosynthesis process.

The underground systems are important for survival of plants and their morphological characteristics have special meaning in environments under disorder. The present study evaluated the existence of preferential allocation of resources in the underground parts of plants resistant to fire and discuss implications of resource allocation and morphology in spatial and temporal dynamics of grassland communities susceptible to fire. The study was restricted to six species of grassland, three monocots (Hypolytrum pulchrum, Echinolaena inflexa and Andropogum sp.) and three eudicots (Euphorbia sarcodes, Eryngium paraguariense and Marcetia taxifolia). The morphological characterizations were performed in about five individuals of each species from anatomical cuts, photos, measurements with digital calipers, tape measures and quantification of biomass share of overhead and underground. The plants showed different spatial arrangements that allow the coexistence in space through a set of skills associated with morphofunctional features integrated aerial and underground parts. Most species showed underground system integrated into networks with preferential allocation of resources to aerial parts, except for E. sarcodes. The morphology is a crucial factor in the competitive responses. The buds developed mainly on rhizomes of plants abundant in these open areas are evidence of the importance of these structures in the dynamics of grassland communities.