Growth Responses of Nutrient-Stressed Cenchrus ciliaris Under Carbon Dioxide Enrichment

Abstract

The response of plants to carbon dioxide (CO 2 ) enrichment is an important aspect to be thoroughly investigated in order to accurately predict the impact on resource use as well ecosystem level responses. But the extent of response of individual plant species is dependent on the underlying biotic and abiotic stresses. In the current project, the response of Cenchrus ciliaris, a C4 grass, was investigated under CO 2 enrichment conditions under nutrient stress. Eco-physiological growth parameters were assessed within two plastic chambers with one chamber kept at ambient CO 2 conditions (500ppm) and the second enriched with CO 2 (1000ppm). Three treatments were studied: ambient (ACO2), enriched (ECO2) and alternating (alternating two weeks in each chamber; ALCO2). High atmospheric CO 2 concentrations did increase shoot and inflorescence production under nutrient stress. The blade area of ECO2 plants was significantly larger than that of ALCO2 plants on the 31st of March 2010 at P=0.06 and on the 7th of April 2010 (P=0.074). Stomatal density of C.ciliaris, however, did decrease for ECO2 and ALCO2. Under ACO2, average sheath biomass was signcantly higher under nutrient stressed condition than under non-stressed condition (65.81% vs. 52.96%; respectively). Growth allocations results revealed a rush toward reproductive production for ECO2 under nutrient stress conditions.

Genotypic Variation for Salinity Tolerance in Cenchrus ciliaris L.

“…Moreover, it would be difficult to determine the critical parameters under field conditions since any environmental change could result in dramatic change in the plant's response to salinity (Shannon, 1997). Although C. ciliaris response to salinity stress has been a topic of many researchers (Arshad et al, 2000; Hacker and Waite, 2001; Jorge et al, 2008; Ksiksi and El-Shaigy, 2012); to best of our knowledge, no study has evaluated and characterized the C. ciliaris genotypes in terms of agro-morphological attributes and dry matter yield responses so far. This study evaluates the morphological and biomass yield responses of C. ciliaris genotypes to water salinity in pot culture trial.…”

Treated municipal wastewater as option to the use of fresh water for the cultivation of valuable pastoral species Buffel grass (Cenchrus ciliaris L.)

“…Nevertheless, a great Na and Cl increase was observed in soil TWW treated; scarce concentration of Na and Cl in C. ciliaris leaves, independently from the ploidy levels, was observed. Salt tolerance in C. ciliaris can be ascribed to the capacity of limiting ion (mainly Na and Cl) uptake by roots and/or ion transport from roots to shoots (Ksiksi & El‐Shaigy, 2012), hindering salt translocation rather than salt absorption (Lanza Castelli et al, 2010). Considering that no significant differences between the two ploidy levels has been observed, salinity tolerance together with scarce concentration of Na and Cl in C. ciliaris leaves could be explained by the efficient mechanism of Na and Cl exclusion of this grass as already reported by al‐Dakheel & Hussain (2016).…”

Strengthening desert plant biotechnology research in the United Arab Emirates: a viewpoint

“…Stressful desert conditions, low water availability or water deficit, temperature stress and salinity are serious threats to rhizobium-legume symbiosis (Sharma et al 2013). All these factors affect soil productivity in numerous ways, including lack of organic matter in the soil and increase in soil salinity, which is worse in hyper-arid desert climates and consequently leads to the deterioration of agricultural crops (Ksiksi and El-Shaigy 2012). Legume plants can play a critical role when integrated as a part of native or agricultural ecosystems with low fertility quality, for instance saline soil, by increasing nitrogen.…”