English

Soares De Lima Geovani,Amilton Dos Santos Junior Jose,Azevedo Xavier Diego,Almeida Dos Anjos Soares Lauriane,Raj Gheyi Hans,Gomes Nobre Reginaldo

doi:10.5897/ajar2015.9606

Abstract

Aiming to evaluate the water relations and gas exchange in castor bean cv. BRS Energia under salinity and cationic nature of irrigation water, an experiment was conducted under controlled conditions in an Ultisol Eutrophic of sandy loam texture. Treatments consisted of six combinations of water salinity (S1– Control (supply water ECw=0.6 dS m-1); S2 - Na+, S3 - Ca2+, S4 - Na++ Ca2+, S5 - K+ and S6 - Na++ Ca2+ + Mg2+all prepared with chloride salt of respective cation and having ECw=4.5 dS m-1, distributed in a randomized block design with four replications. The use of saline water of distinct cationic nature affected the water relations of the castor bean, the least deleterious effects were observed in plants irrigated with potassic water The negative effects of the cationic nature of irrigation water were more evident in gas exchange at 40 days after sowing (DAS), the highest values for stomatal condutance, transpiration rate, assimialation of CO2, instantaneous carboxylation efficiency and intrinsic water use efficiency were observed in case of potassium ion. The castor bean 'BRS Energia' is more sensitive to the presence of sodium ions in the irrigation water, both in terms of water relations as well as for gas exchange. Key words: Ricinus communis L., salt stress, semiarid.

Highlights

The demand for vegetable oils is growing every year and the global interest in oilchemical industry is high, given its application in diverse forms
Among the physiological indices affected by salinity stand outs the CO 2 assimilation rate, transpiration, stomatal conductance and internal CO2 concentration, which can be inhibited by accumulation of Na and/or Cl in chloroplasts, affecting biochemical and photochemical processes involved in photosynthesis (Taiz and Zeiger, 2013). Associated with this is the interferences of salts in the water relations of the plants that are reflected in osmotic potential, relative water content and saturation water deficit in leaf, in addition to the ion toxicity and imbalance of nutrient absorption causing widespread reduction of growth with serious damage in productivity (Ahmed and Moritani, 2010)
Considering understanding of changes in water relations and physiological responses of plants grown under the influence of abiotic stress, such as saline, can provide important tools to aid in the management of species irrigated with saline waters, this study proposed to evaluate the water relations and gas exchange in the castor bean cv

Summary

INTRODUCTION

The demand for vegetable oils is growing every year and the global interest in oilchemical industry is high, given its application in diverse forms. Among the physiological indices affected by salinity stand outs the CO 2 assimilation rate, transpiration, stomatal conductance and internal CO2 concentration, which can be inhibited by accumulation of Na and/or Cl in chloroplasts, affecting biochemical and photochemical processes involved in photosynthesis (Taiz and Zeiger, 2013) Associated with this is the interferences of salts in the water relations of the plants that are reflected in osmotic potential, relative water content and saturation water deficit in leaf, in addition to the ion toxicity and imbalance of nutrient absorption causing widespread reduction of growth with serious damage in productivity (Ahmed and Moritani, 2010). BRS Energia irrigated with saline water of distinct cationic nature

MATERIALS AND METHODS

RESULTS AND DISCUSSION

Conclusions