A few years back, there was discussion centered on Switzerland about the dignity of plants. A provision had been added to the Swiss Federal Constitution requiring that the Confederation legislate on use of reproductive and genetic material in such a way as to take into account the dignity of living beings, and the Swiss Federal Ethics Committee on Non-Human Biotechnology looked into the question of how the dignity of plants as living things should play a role in reasoning about these matters. The way the Committee understood dignity was as indicating that something is morally considerable for its own sake.
It's not very difficult to argue that plants should have moral consideration for their own sake; strict Kantians wouldn't accept, but most people are already committed to ideas that require that plants have dignity in this minimal sense. We can make perfect sense of the idea that plants have their own interests, for instance; these interests may not be conscious, but we can clearly identify things as benefiting and harming plants on their own terms. Unsurprisingly, though, the Committee had some difficulty coming up with definite ways in which the dignity of plants could be harmed, and (since the constitutional provision only requires that the dignity of living things be taken into account, not that it be treated as a fundamental value the way the constitution treats human dignity) an even harder time coming up with ways in which that dignity could be so harmed as to be definitely unacceptable in a law concerned with reproductive or genetic material. One possible case they suggested was when a plant's reproductive ability is so harmed that they couldn't reproduce, but as was pointed out in response, large numbers of plants are actually bred specifically for this, like seedless fruits.
I think a complication is that people tend to assume that dignity immediately gives obligations. This is so in the Kantian account of dignity, for instance. But understanding dignity as being 'worth moral consideration for its own sake', there is no obvious reason why you would treat dignity as having such a close relationship with obligation. Indeed, it makes sense only to consider there to be any obligation when, in some way, the goods of the plant being considered are common good in need of protection. But you can still hold that the goods of a plant are genuine goods, so it's better to give them some thought than none at all. The dignity of plants would not impose any definite obligation, but it need not be the less real for all that, and it would make some courses of action better than others in some way, even if not in every way.
On this ground, I think the Committee's suggestion makes a certain kind of sense. We don't have an obligation to grapes to ensure the integrity of their reproductive systems. But it's still the case that being able to reproduce is part of the good of a plant, and it's still the case that it's a good worth taking into account. Obviously we made seedless grapes, stunting the growth of their seeds, because there are other goods being considered. But one could argue that it would be best to do this in a way that doesn't harm their reproductive ability, if such a way is possible. Some fruits, like tomatoes and pineapples, are effectively seedless as long as they are not pollinated; such seedlessness is obviously not a problem. Other kinds of seedless fruits, like seedless watermelons, are actually grown from seeds, because they are always hybrids, and so are the sterile mules of the plant kingdom; this particular plant won't have fully developed seeds, but it would naturally occur in nature and its reproduction is not dependent on us. Seedless grapes are not in either of these groups; their reproduction depends entirely on us, because to multiply they must be grafted into other plants. Their reproduction is artificial. One could very reasonably say that this is not ideal for the grapes, and one could very reasonably say that, knowing this, we should put some thought into whether it is better to impose such a non-ideal situation on grapes. Again, it's not an obligation; it's just that, because it's non-ideal for the grapes, it's better think about whether it's really worth imposing it on them before you do it.
Of course, what would go for plants would go a fortiori for animals and a fortiorior
Various Links of Interest
* Kirk Kanzelberger, Reality and the Meaning of Evil
* Timothy O'Malley, What's Next After Catholic Colleges Decline?
* Philip Christman, David Bentley Hart Reviews the New Kanye. This parody is absolutely spot on.
* Ken White looks at common mistakes made in discussing free speech in the American legal context. (Short answer: if it's not directly obscenity, defamation, fraud, or incitement, it's definitely included under freedom of speech, and even those exceptional categories are very narrowly understood, so something might count colloquially but still fall under freedom of speech.)
* Candace Vogler, A Spiritual Autobiography
* David Novak, Does Natural Law Need Theology? at First Things.
* Russell Blackford, Science Fiction as a Lens into Future War. I'm not sure how much it tells us about future war, but it's an interesting look at how science fiction handles the topic.
* Cyrus Zargar, Storytelling and the Pursuit of Virtue in Islam
* James Franklin, Discrete and continuous: A fundamental dichotomy in mathematics (PDF)
* Vincenzo & Iacona, The evidential conditional (PDF)
H. P. Lovecraft, The Whisperer in the Dark
Michael Gregorio, Critique of Criminal Reason
Isaac Asimov, Second Foundation
Douglas Walton, Informal Logic: A Pragmatic Approach
Fred Kaplan, John Quincy Adams: American Visionary