軟木脂是一種植物細(xì)胞間的蠟狀物質(zhì),，用來防止水穿越組織。普渡大學(xué)的科學(xué)家發(fā)現(xiàn)變異的擬南芥品種可以產(chǎn)生兩倍的軟木脂,，因此他們相信調(diào)控這種物質(zhì)可以使植物更好的吸收養(yǎng)分。相關(guān)文章發(fā)表于新一期的PLoS Genetics,。
David Salt和同事發(fā)現(xiàn)基于軟木脂濃度的特定養(yǎng)分進(jìn)入植物根部的途徑,，通過調(diào)節(jié)軟木脂在根部的量，植物可以更容易的吸收有益營養(yǎng)物質(zhì),。擁有更多軟木脂的植物葉中鈣,、錳和鋅的含量更少,，鈉、硫和硒的含量更高,。“和動物一樣,，植物也有選擇性的攝入物質(zhì)，”Salt說,，“它們需要某種量的鉀或氮,。”它們產(chǎn)生的軟木脂量決定它們這些選擇。
Salt等人還發(fā)現(xiàn)這種含兩倍蠟狀物質(zhì)的植物可以啟動防萎蔫機制,。因為軟木脂可以限制水份吸收,，植物將減少蒸騰作用，或葉子的蒸發(fā)作用,?？刂栖浤局赡苡兄陂_發(fā)水利用率高的植物。（生物谷Bioon.com）
生物谷推薦原始出處：
PLoS Genet 5(5): e1000492. doi:10.1371/journal.pgen.1000492
Root Suberin Forms an Extracellular Barrier That Affects Water Relations and Mineral Nutrition in Arabidopsis
Ivan Baxter1, Prashant S. Hosmani2, Ana Rus2, Brett Lahner2, Justin O. Borevitz3, Balasubramaniam Muthukumar2, Michael V. Mickelbart2, Lukas Schreiber4, Rochus B. Franke4, David E. Salt1,2*
1 Bindley Bioscience Center, Purdue University, West Lafayette, Indiana, United States of America, 2 Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana, United States of America, 3 Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, United States of America, 4 Institute of Cellular and Molecular Botany, University of Bonn, Bonn, Germany
Though central to our understanding of how roots perform their vital function of scavenging water and solutes from the soil, no direct genetic evidence currently exists to support the foundational model that suberin acts to form a chemical barrier limiting the extracellular, or apoplastic, transport of water and solutes in plant roots. Using the newly characterized enhanced suberin1 (esb1) mutant, we established a connection in Arabidopsis thaliana between suberin in the root and both water movement through the plant and solute accumulation in the shoot. Esb1 mutants, characterized by increased root suberin, were found to have reduced day time transpiration rates and increased water-use efficiency during their vegetative growth period. Furthermore, these changes in suberin and water transport were associated with decreases in the accumulation of Ca, Mn, and Zn and increases in the accumulation of Na, S, K, As, Se, and Mo in the shoot. Here, we present direct genetic evidence establishing that suberin in the roots plays a critical role in controlling both water and mineral ion uptake and transport to the leaves. The changes observed in the elemental accumulation in leaves are also interpreted as evidence that a significant component of the radial root transport of Ca, Mn, and Zn occurs in the apoplast.
