{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

PltSensorySysts-Chpt.40

PltSensorySysts-Chpt.40 - PLANT SENSORY SYSTEMS CHAPTER 40...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
PLANT SENSORY SYSTEMS CHAPTER 40 and 41 This chapter is equivalent to the two chapters on the nervous system and endocrine systems for animals! Plants respond much like animals to all sorts of environmental cues, but “homeostasis” is not a part of their life history. The first part of Chapter 41 is included because of the connection to flowering. Plants “sense” environmental cues such as light, gravity, touch, hydration (or lack thereof), and temperature and convey these signals by transduction to the appropriate cells (Fig. 40.4). We see this process on a macroscopic scale, but the signaling is at the cellular level. Plants respond to light – Pp 808 – 809: One needs to distinguish between photomorphogenesis and phototropism . Photomorphogenesis is discussed at the beginning of Chpt. 41 – pp 832 – 837. Personally, I find these two terms to be overlapping and the use of both to be confusing. However………. Red receptors often trigger photomorphogenesis (Fig. 40.2; 41.2) – changes in morphological growth due to light. It is true that plants go through metamorphosis much like their animal counter-parts. This is called “ competence ” and it is the internal development that allows plants to obtain competence to respond to a stimulus. This process in plants is called “ phase change ” in contrast to metamorphosis. Adults may or may not produce reproductive structures depending on a large host of environmental cues. One cue is light – Fig. 40.2. Figure 40.2 describes how the plant responds to Phytochrome (and actually, there are several different phytochrome molecules). Notice from Fig. 40.2, the plant can measure daylight length (by measuring the degredation of P fr – Fig. 41.6). This is termed “ photoperiodism .” As a result there are “long-day” and “short-day” plants. There are also “ day neutral ” - plants. Photoperiod can be manipulated artificially so that plants flower at a certain time. Causing Poinsettias to flower at the winter holiday season is a good example (Fig. 41.7). There are applications as well. For example, why doesn’t ragweed grow in Maine? Plant flowering also responds to temperature. This is called “ vernalization .” This is also called a “ temperature-dependent pathway which contrasts with the “light-dependent” pathway above.
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern