Figure 6.

Stromules formed in close proximity to the nucleus usually face it. (A) Schematic outline of the method used for the rough determination of whether a stromule faces toward or away from the nucleus. The distance of the base of the stromule as well as the tip of the stromule to the nucleus were measured and compared. If the stromule tip is further from the nucleus than the base of the stromule (any stromule tip falling within the pink part of the circle for the plastid illustrated here) the stromule would be considered facing away from the nucleus, while any tip that is closer to the nucleus than the base (all those falling within the blue part of the circle) would be considered as facing toward the nucleus. (B) Illustration of example measurements taken from a real cell showing four plastids without stromules (green), one with a stromule and plastid body touching the nucleus (yellow), two that were considered to be facing the nucleus (blue), and one that was considered to be facing away from the nucleus (red). Example calculations for a stromule facing the nucleus (i.e., stromule decreasing the distance between the nucleus and plastid body), and a stromule facing away from the nucleus (i.e., stromule increasing the distance between the nucleus and the plastid body), are outlined in blue and red, respectively. Cell border outlined in gray, nucleus outlined in dark red. (C) Bar chart illustrating the percentage of stromules facing the nucleus (as determined by the criteria outline in A,B) with increasing distance from the nucleus in small (yellow), medium (green), and large (blue) cells.