Biochemistry and physiology of the inorganic nutrients working in the apoplast of higher plants

我们已经发现，必需的植物营养元素硼（B）的工程交联果胶多糖链在鼠李糖半乳糖醛酸聚糖II（RG-II）的网站沿着链。在交联过程中，Ca^2+离子也参与了链的连接，但Al离子干扰了键合。Matoh和他的同事纯化了一些负责糖的酶，这些酶是RG-II特有的，一种KDO合酶，其DNA被克隆和测序。Fujiwara等揭示高等植物通过B特异性膜蛋白主动吸收B。对该蛋白及其DNA进行了克隆和测序。B转运蛋白在内皮中起作用。Ma研究了大麦根细胞壁中Al的结合位点。铝离子与细胞壁果胶多糖结合，但仅通过其与外表皮的结合而产生不良作用。

We have revealed that the essential plant nutrient element boron (B) works to cross-link pectic polysaccharide chains at the rhamnogalacturonan II (RG-II) sites along the chain. In the cross-link, Ca^<2+> ions are also involved to connect the chains, but Al ion interferes with the bonding. Matoh and his colleague purified some enzymes which are responsible for the sugars which particular to RG-II, a KDO synthase, and its DNA was cloned and sequenced. Fujiwara et al revealed that B is actively taken up by higher plants through a B-specific membrane proteins. The protein and its DNA was cloned and sequenced. The B transporter works in the endodermis. Ma studied the binding sites for Al in barley root cell walls. Aluminum ion binds to cell wall pectic polysaccharides, but it works the adverse effect only by which binds to the outer epidermis.