Salt Tolerance of Higher Plants and Uptake of Inorganic Nutrients

植物の耐塩性を調べるため,39種類の植物を用いて,NaCl,およびNa2SO,で塩処理(0～60meq/l)を行い,成育に対する影響,体内無機成分含量について検討した.その結果,アツケシソウは例外的に高塩濃度で成育が著しく促進され,NaとClあわせて乾物重の50%以上を占めた.植物の成育から耐塩性を判断した場合,耐塩性の強い植物として,ワタ,イタリアンライグラス,ハツカダイコン,ハゲイトウ,ホウレンソウ,アシ,イグサなど14種類があげられる.中程度の耐塩性を示す植物はセルリー,カブ,オクラ,アスパラガスなど14種類であった.耐塩性の弱いものはキュウリ,ナタネ,タバコ,シソなど11種類であった.これらの植物の茎葉のNa含量は0.8～8%(アツケシソウを除く)まで分布し,K,Ca,Mgの吸収が阻害されていた.しかし耐塩性(成育の阻害)とNa含量,あるいはK,Ca,Mgの吸収阻害の間には相関性は認められず,今後,耐塩性の機構についての検討が必要である.塩類処理による果実や子実の成育阻害は,茎葉のそれより影響が大きかった

Walk Ratio: Perception of an Invariant Parameter of Human Walk on Virtual Characters

International audienceSynthesizing motions that look realistic and diverse is a challenging task in animation. Therefore, a few generic walking motions are typically used when creating crowds of walking virtual characters, leading to a lack of variations as motions are not necessarily adapted to each and every virtual character’s characteristics. While some attempts have been made to create variations, it appears necessary to identify the relevant parameters that influence users’ perception of such variations to keep a good trade-off between computational costs and realism. In this paper, we therefore investigate the ability of viewers to identify an invariant parameter of human walking named the Walk Ratio (step length to step frequency ratio), which was shown to be specific to each individual and constant for different speeds, but which has never been used to drive animations of virtual characters. To this end, we captured 2 female and 2 male actors walking at different freely chosen speeds, as well as at different combinations of step frequency and step length. We then performed a perceptual study to identify the Walk Ratio that was perceived as the most natural for each actor when animating a virtual character, and compared it to the Walk Ratio freely chosen by the actor during the motion capture session. We found that Walk Ratios chosen by observers were in the range of Walk Ratios measured in the literature, and that participants perceived differences between the Walk Ratios of animated male and female characters, as evidenced in the biomechanical literature. Our results provide new considerations to drive the animation of walking virtual characters using the Walk Ratio as a parameter, and might provide animators with novel means to control the walking speed of characters through simple parameters while retaining the naturalness of the locomotion