Experiment 1: Plant Response

With this experimental setup, Scott conducted two experiments. One experiment tested the immediate response of the plants to the insect feeding. In this case, the insects fed for 30 minutes. Then leaf tissue from plants was sampled to determine how the plants controlled their stress-response hormone in the signal pathway.

Scott collected the following data from the “Plant Response” experiment. He had two types of plants; wild-type (WT) and mutant (jar1). He treated these plants with the addition of a set number of cabbage loopers that fed for 30 minutes. He likewise had a control; both the WT and jar1 plants in the same environment without the cabbage looper feeding. He then sampled leaf tissue at 0, 30, 60, 90, and 120 minutes after the feeding and measured JA-Ile content of the leaf tissue. The table below represents the data obtained from one replication of this experiment.

Table 1. JA-Ile levels (pmole g-1) after insect feeding
Time sample collected WT with insect feeding jar1 with insect feeding WT unwounded (No feeding) jar1 unwounded (No feeding)
0 min. 17 1 1 1
30 min. 21 3 1 1
60 min. 37 3 1 1
90 min. 35 2 2 2
120 min. 7 2 1 1

From this data Scott could draw a graph to create a visual display of plant response to the treatments measured by their production of JA-Ile. The graph below is plotting two columns of the data.

Type A has a higher JA-lle accumulation than B does during a 30-minute feeding on Arabidopsis



The graph above has plotted two of the columns of data from the plant response to feeding experiment.  Which line is showing the data from the jar1 with insect feeding?

Looks Good! Correct: jar1 goes with line B since it has a much lower response as measured by JA-Ile synthesis than the wild-type.
WT (unwounded), jar1 (unwounded) and jar1 all have low JA-lle accumulation in response to 30 minutes of feeding on Arabidopsis. The wild type is much, much higher.



Based on the JA-Ile graph above made from all the data in Table 1, Scott could conclude that…

Looks Good! Correct: jar1 has the same JA-Ile response as the wild-type control plants. The mutation prevents these plants from mounting a normal response to the insect feeding.