题干

图一是将含有生长素的琼脂块放在切去尖端的胚芽鞘的一侧,胚芽鞘弯曲的情况(弯曲角度用A表示);图二是生长素对胚芽鞘生长的促进作用示意图,由此我们可以判断下列说法错误的是

A:琼脂块中生长素浓度在b点时A具有最大值

B:当生长素浓度小于b点浓度时,随生长素浓度的增加A逐渐减小

C:只有生长素浓度高于c点浓度时,生长素才会抑制胚芽鞘的生长

D:由右图可知生长素对于胚芽鞘的生长作用具有两重性

上一题 下一题 0.0难度 选择题 更新时间:2015-12-09 06:06:05

答案(点此获取答案解析)

A

同类题3

阅读理解

                                                                  Warley Woods Community (社区) Trust

    Welcome to our third news letter of the year!

    Our main activity for March is our Walk for the Woods fundraising events on Saturday, 17th March, starting any time between 10 a.m. and 2 p.m. We will be walking the distance between Warley Woods and Tipperary. It is indeed a long way — 80 miles. The more people that you can get sponsor you, the more money we can raise to helplook after our beautiful woodland. More information is available at ourwebsite.

    The Sunday volunteers planted two beeches and an oak last week. This was thanks to the money from the Big Tree Plant and to Lisa and Gordon Whitiker, whose friends gave money forthe big trees instead of for their wedding presents. Thanks to everyone who took part.

    There were 15 volunteersat the Oral History Training Day which was led very ably by Julia Letts. The group will be meeting again and will start to interview the local people whohave offered to tell their stories. We are happy to hear from others who would like to be interviewed about their memories of the Woods for the project. If you or anyone you know is interested, please call Viv Cole at the office. This project is financed by Heritage Lottery Fund.

    There was a huge response to the Forest Schools activities held at half term. These will be held again during the Easter holidays on the following dates: 4th April from 10 a.m. to 3 p.m. for over 8s. On 12th April form 10 a.m. to 12 noon, there will be a Teddy Bears' Picnic for the under 8s. All these must be booked in advance.

    Finally, don't forget the Easter Egg Roll on Bank Holiday, 9th April, staring at 11 a.m. Bring your ownhard-boiled and decorated egg to roll down the hill in the woods. The firstpast the finishing line will win a large chocolate egg! This year, due to popular demand, there will also be an Adults' Easter Egg Roll following the children's competition.

    We look forward to seeing you all soon, at one of our many events.