On the boron deficiency in plants. Ⅴ. Boron requirements of barley

Authors gained the following results from the water culture of barely. 1) Boron is essential to keep the normal growth of barley. For the life cycles of barley, boron above 0.003 p.p.m. must be contained in the culture solutions. 2) Growth and yields of barley is highest in culture solution containing 0.05 p.p.m. boron. Injury symptoms of boron excess appeared on the barley grown in solution having 0.5 p.p.m. boron. 3) Unusual many tillers developed out by boron deficiency. And elongation of stem also checked. So, the shape of barley became bushy. 4) Ripening of barley grains affected by boron concentration in culture solutions.著者の一人（平井）は曩にヒエに就いて研究した結果，単子葉植物の硼素所要量は著るしく双子葉植物より少いこと(約1/10)を知つた．Waringtonが大麦では水耕，土耕いずれに於ても硼素が影響なしとのべたのは，恐らくこの所要量の少ないことのためによる見落しの結果であるかと思われる．そこで著等等は水耕でもつて大麦を栽培して， 硼素含量が(培養液内の)その生育にどんな影響を与えるか， 硼素缺乏によつてどんな症状を現出するかを試みてみることにした．その結果えたる処を以下記述報薯する