Plants and Climate Change

Is climate change affecting how plants reproduce? That’s the question behind a project launching at San Diego State and 18 other California Universities. Here’s a look at the scientists taking part in this critical research to understand the relationship between what our local plants tell us about global issues.


Is climate change affecting how plants reproduce?

That's the question behind a project launching at San Diego State and 18 other California universities.

Here's a look at the scientists taking part in this critical research to understand the relationship between what our local plants tell us about global issues.

This is a very diverse area.

Just as Interstate 8 drops down the bouldery pass into the Imperial Valley, a stone structure called Desert View Tower has offered motorists sweeping views of the desert floor since 1923.

You probably need to label this one.

Now it could offer a glimpse into how climate change is affecting native plants.

You know what?

Let's go to the one on the top.

Lluvia Flores-Rentería is an evolutionary plant ecologist at San Diego State University.

The tower's owners are letting her and her students track the reproductive cycle of the cholla cacti on their property.

Cylindropuntia wolfii is the scientific name, but the common name is Wolfii's cholla.

Wolf's cholla is common in Southern California's desert, waist-high tangles of cylindrical sections covered in fine spines.

At sunset, the spines catch the sunlight and give off a show-stopping glow.

But Flores-Rentería and master's student Ryan Buck noticed this year the chollas skipped their spring show of red and yellow blooms -- except those at the tower.

They fared better thanks to a weekly drink of water.

So the two are back to see if the flowers developed fruit and, in them, seeds.

So, if you see a large fruit that looks juicy, let me know.

Studies on the East Coast have found widespread changes in plant reproductive cycles as the Earth warms.

The fruit is also dry.

On the West Coast, a $1.5 million grant from the National Science Foundation will help researchers like Flores-Rentería ask whether that's happening here and whether it's linked to climate change.

This time, this year, we've seen a shift.

But we don't know if it's related to precipitation patterns or temperature or something else, right?

So if we have historical data, then we can start asking these questions.

And all of these go... These are ferns, fern relatives.

That historical data lives here pressed onto paper and filed away in cabinets deep in the Life Sciences Building at San Diego State.

And just pulling this out, this was collected in 1941, April 30.

There's a lot of detail that we can study.

We could dissect the flower.

We could soak it up in boiling water.

We could look at the fruits.

We can look at the plant hairs, called trichomes.

So we can still see a lot, even though this is nearing 100 years old.

But we can also take that leaf and extract DNA.

With the NSF grant, herbaria across the state will upload high-resolution photos of their specimens and information about where and when they were collected to a central online database.

As we do this for all of California, we can begin to get an idea as to when they flowered, when they fruited in the past versus the present.

And they can use a digital map to make comparisons by location.

One hypothesis is they're today flowering earlier in the season.

And we don't have enough data to prove that, but I think we'll have enough data in about three years.

Back at Desert View Tower, Flores-Rentería scours cholla after cholla, looking for fruit.


Well, I cannot really find anything.

That's sad.

Even on the sections covered with protective bags where Flores-Rentería pollinated the flowers by hand, the fruit dried out before it could mature.

The other thing is that when we came here and we did the pollinations, the manual pollinations, we also had... We saw the bees.

The bees were very active.

So that's very important, so the natural pollenization occurred, and our manual pollenization occurred, but as you can see, all of the fruits are being aborted.

So that's kind of scary, really, to see all of these plants not reproducing sexually.

The plant can still clone itself by dropping sections off its branches to take root elsewhere.

No fruits formed.

But student Ryan Buck says the adaptation isn't a failsafe.

Just imagine that you bud off and you start cloning, and there's just a whole population of you.

And let's say you're allergic to strawberries, and the only food source you have is strawberries.

Every single one of you is going to die because you can't eat.

So there's not enough genetic diversity to keep going if it's just budding and cloning off the whole time.

Some species can evolve and adapt to that, but that's going to take a lot of time, and at the rate that climate change is going, they don't have that much time.

And the plants will look a lot drier.

Buck and Flores-Rentería will continue to track the cholla to see if this year is an anomaly or a symptom of climate change.

In the meantime, they'll take the spiky, dried fruit back to the office to see if they can salvage some seeds.