Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Aims</jats:title> <jats:p>Since gravitropism is one of the primary determinants of root development, facilitating root penetration into soil and subsequent absorption of water and nutrients, we studied this response in rice.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>The gravitropism of 226 Chinese rice micro-core accessions and drought-resistant core accessions were assessed through the modified gravity-bending experiment and genome-wide association analysis (GWAS) was used to map the associated QTLs.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>The average value of gravitropic response speed of seminal roots was 41.05°/h, ranging from 16.77°/h to 62.83°/h. The gravity response speed of <jats:italic>Indica</jats:italic> (42.49°/h) was significantly (P &lt; 0.002) higher than <jats:italic>Japonica</jats:italic> (39.71°/h) subspecies. The gravitational response speed of seminal roots was significantly positively correlated with the number of deep roots (r = 0.16), the growth speed of seminal roots (r = 0.21) and the drought resistance coefficient (r = 0.14).</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>In total, 3 QTLs (quantitative traits) associated with gravitropic response speed were identified on chromosome 4, 11 and 12. There are some known QTLs relating to roots traits and drought resistance located nearby the QTLs identified here, which confirms the close relationship between radicle gravitropism and the drought resistance. From within these intervals, 5 candidate genes were screened and verified by qPCR in a few rice varieties with extreme phenotypic values, demonstrating that gene LOC_Os12g29350 may regulate gravitropism negatively. This may be a promising candidate to be confirmed in further studies.</jats:p> </jats:sec>

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Background and Aim</jats:title> <jats:p>Drought is the main abiotic stress affecting Mediterranean forests. Root systems are responsible for water uptake, but intraspecific variability in tree root morphology is poorly understood mainly owing to sampling difficulties. The aim of this study was to gain knowledge on the adaptive relevance of rooting traits for a widespread pine using a non-invasive, high-throughput phenotyping technique.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>Ground-Penetrating Radar (GPR) was used to characterize variability in coarse root features (depth, diameter and frequency) among populations of the Mediterranean conifer <jats:italic>Pinus halepensis</jats:italic> evaluated in a common garden. GPR records were examined in relation to aboveground growth and climate variables at origin of populations.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>Variability was detected for root traits among 56 range-wide populations categorized into 16 ecotypes. Root diameter decreased eastward within the Mediterranean basin. In turn, root frequency, but not depth and diameter, decreased following a northward gradient. Root traits also varied with climatic variables at origin such as the ratio of summer to annual precipitation, summer temperature or solar radiation. Particularly, root frequency increased with aridity, whereas root depth and diameter were maximum for ecotypes occupying the thermal midpoint of the species distribution range.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusion</jats:title> <jats:p>GPR is a high-throughput phenotyping tool that allows detection of intraspecific variation in root traits of <jats:italic>P. halepensis</jats:italic> and its dependencies on eco-geographic characteristics at origin, thereby informing on the adaptive relevance of root systems for the species. It is also potentially suited for inferring population divergence in resource allocation above- and belowground in forest genetic trials.</jats:p> </jats:sec>