Plant Biology is fascinating I would like to highlight an outstanding website that will support your learning of the topic http://www.saps.org.uk/
It has a variety of resources to help your learning and even give you ideas on possible experiments to conduct.
As spring is upon the Northern hemisphere with summer quickly approaching, have a look at this link that leads you through possible lines of inquiry to support your extended essay or possibly your internal assessment project. On the right side of the page you will see links to past studies such as this one. Word of warning: make sure you properly reference all sources. Using a standard method is acceptable, but you should explain how you adopted it to your own work.
And its not all about plants growing or photosynthesising. The website provides protocols for investing cellular respiration.
Animations focus on transport, respiration and photosynthesis, and you will find student notes, again, on the left side of the web page.
Below you will find a video on photoperiodicity. Such you watch it in conjunction with this animation .
One last word on referencing – it is NOT enough to simply list your sources at the end in a bibliography. They MUST be cited in the main body of your work as appropriate.