If grain from outside Israel was brought into Israel, it is obligated in challah. If grain went from Israel to outside Israel, Rabbi Eliezer says it is obligated in challah but Rabbi Akiva says that it is exempt.
If soil with seeds planted in it is transported from outside Israel to Israel by ship, the produce it yields is obligated in tithes and the laws of the sabbatical year. Rabbi Yehuda says that this only applies once the ship touches the land of Israel. Dough that was kneaded with fruit juice is obligated in challah (just like regular bread) but one need not ritually wash to eat it (unlike regular bread).