Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Aims</jats:title> <jats:p>Root system is an important regulator for unevenly distributed below-ground resource acquisition. In a rainfed cropping environment, drought stress (DS) significantly restricts root growth and moisture uptake capacity. The fact that silicon (Si) alleviates DS in wheat is widely reported, but its effects on the wheat root system remain unclear.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>The present study investigated the effect of pre-sowing Si treatment on two contrasting wheat cultivars (RAC875, drought-tolerant; Kukri, drought-susceptible) at early growth stages. The cultivars were grown in a glasshouse in a complete randomized design with four replications and two watering treatments. Various root traits and physiological data, including non-destructive infrared thermal imaging for water stress indices, were recorded.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>Under DS and Si (DSSi), Kukri had a significant increase in primary root length (PRL,44%) and lateral root length (LRL,28.1%) compared with RAC875 having a substantial increase in PRL (35.2%), but non-significant in LRL. The Si-induced improvement in the root system positively impacted canopy physiology and significantly enhanced photosynthesis, stomatal conductance and transpiration in Kukri and RAC875 under DSSi. Canopy temperature was reduced significantly in Kukri (4.24%) and RAC875 (6.15%) under DSSi, while canopy temperature depression was enhanced significantly in both the cultivars (Kukri,78.6%; RAC875, 58.6%) under DSSi.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusion</jats:title> <jats:p>These results showed that Si has the potential to influence below-ground traits, which regulate the moisture uptake ability of roots for cooler canopy and improved photosynthesis under DS. It also suggests a future direction to investigate the underlying mechanisms involved in wheat’s Si-induced root growth and moisture uptake ability.</jats:p> </jats:sec>

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Aims</jats:title> <jats:p>Nitrogen deficiency in eco-engineered technosol from iron (Fe) ore tailings limits the productivity of colonising soil microbes and pioneer plants, which are critical to further development of the technosol. Symbiotic biological N<jats:sub>2</jats:sub> fixation may be a strategy to supply N in the moderately alkaline early technosols since native legumes such as <jats:italic>Acacia auriculiformis</jats:italic> are tolerant of saline and alkaline soil conditions as those in the technosol. It is hypothesized that tolerant native legume <jats:italic>A. auriculiformis</jats:italic> could form functional nodules to fix N<jats:sub>2</jats:sub> when grown in early eco-engineered technosols.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p><jats:italic>A. auriculiformis</jats:italic> growth and root nodulation in the early tailing technosols were investigated using a glasshouse experiment, and plant N<jats:sub>2</jats:sub> fixation was evaluated using the <jats:sup>15</jats:sup> N natural abundance isotope method. Key factors influencing root nodulation and N<jats:sub>2</jats:sub> fixation have also been evaluated, including water supply and phosphorous nutrition.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>The results indicated that <jats:italic>A. auriculiformis</jats:italic> grew well in the tailing technosols and naturally formed nodules with rhizobia. The nodules were functional in N<jats:sub>2</jats:sub> fixation, leading to improved plant N nutrition. The nodulation and N<jats:sub>2</jats:sub> fixation were severely limited by water deficiency stress. Improved phosphorous supply favoured nodulation and N<jats:sub>2</jats:sub> fixation by <jats:italic>A. auriculiformis</jats:italic> plants under water deficiency stress.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>These findings suggested that <jats:italic>A. auriculiformis</jats:italic> could grow in early tailings technosols and fixed N<jats:sub>2,</jats:sub> and proper water and phosphorous fertilizer management could improve <jats:italic>Acacia</jats:italic> plant’s performance and N<jats:sub>2</jats:sub> fixation functions. It is possible to introduce tolerant native legumes such as <jats:italic>A. auriculiformis</jats:italic> to improve N supply in the early technosols.</jats:p> </jats:sec>

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Background and aims</jats:title> <jats:p>Paddy management results in frequent redox cycles of the soil and thus changes in the terrestrial iron (Fe) cycle. We intended to test that the increasing duration of paddy management and the increasing frequency of soil redox cycles leave their fingerprint on Fe isotope composition of paddy systems, which could subsequently be used to deduce the origin of rice plants as related to the extent of past soil paddy management.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>We sampled soil and rice plants of a paddy chronosequence in China with rice cultivation history up to 2000 years and determined the changes of soil Fe pools and Fe isotope composition of the soil and rice plants.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>Prolonged paddy management reduced Fe concentrations in submerged topsoil leading to an enrichment of heavy Fe isotopes, with the δ<jats:sup>56</jats:sup>Fe values 0.12‰ heavier than the parent material after 2000 years. Particularly, Fe oxides were lost quickly, while exchangeable and organic-associated Fe continuously accumulated during paddy management and played an increasing role in the plant-available Fe pool in the topsoil. The Fe content in rice also increased with paddy age, while its Fe isotope composition did not reflect that of paddy soil but resembled that of the Fe plaques on the roots.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusion</jats:title> <jats:p>Prolonged rice cropping altered the biological contribution in the terrestrial Fe cycle. However, while soil Fe pools that are closely linked with biological activities were affected rather quickly, the changes in the whole soil Fe system were detectable only after a millennium of paddy management.</jats:p> </jats:sec>