Can plants be altruistic? You bet, says new CU-Boulder-led study
Feb 4th
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We’ve all heard examples of animal altruism: Dogs caring for orphaned kittens, chimps sharing food or dolphins nudging injured mates to the surface. Now, a study led by the University of Colorado Boulder suggests some plants are altruistic too.
The researchers looked at corn, in which each fertilized seed contained two “siblings” — an embryo and a corresponding bit of tissue known as endosperm that feeds the embryo as the seed grows, said CU-Boulder Professor Pamela Diggle. They compared the growth and behavior of the embryos and endosperm in seeds sharing the same mother and father with the growth and behavior of embryos and endosperm that had genetically different parents.
“The results indicated embryos with the same mother and father as the endosperm in their seed weighed significantly more than embryos with the same mother but a different father,” said Diggle, a faculty member in CU-Boulder’s ecology and evolutionary biology department. “We found that endosperm that does not share the same father as the embryo does not hand over as much food — it appears to be acting less cooperatively.”
A paper on the subject was published during the week of Jan. 21 in the Proceedings of the National Academy of Sciences. Co-authors on the study included Chi-Chih Wu, a CU-Boulder doctoral student in the ecology and evolutionary biology department and Professor William “Ned” Friedman, a professor at Harvard University who helped conduct research on the project while a faculty member at CU-Boulder.
Diggle said it is fairly clear from previous research that plants can preferentially withhold nutrients from inferior offspring when resources are limited. “Our study is the first to specifically test the idea of cooperation among siblings in plants.”
“One of the most fundamental laws of nature is that if you are going to be an altruist, give it up to your closest relatives,” said Friedman. “Altruism only evolves if the benefactor is a close relative of the beneficiary. When the endosperm gives all of its food to the embryo and then dies, it doesn’t get more altruistic than that.”
In corn reproduction, male flowers at the top of the plants distribute pollen grains two at a time through individual tubes to tiny cobs on the stalks covered by strands known as silks in a process known as double fertilization. When the two pollen grains come in contact with an individual silk, they produce a seed containing an embryo and endosperm. Each embryo results in just a single kernel of corn, said Diggle.
The team took advantage of an extremely rare phenomenon in plants called “hetero-fertilization,” in which two different fathers sire individual corn kernels, said Diggle, currently a visiting professor at Harvard. The manipulation of corn plant genes that has been going on for millennia — resulting in the production of multicolored “Indian corn” cobs of various colors like red, purple, blue and yellow — helped the researchers in assessing the parentage of the kernels, she said.
Wu, who cultivated the corn and harvested more than 100 ears over a three-year period, removed, mapped and weighed every individual kernel out of each cob from the harvests. While the majority of kernels had an endosperm and embryo of the same color — an indication they shared the same mother and father — some had different colors for each, such as a purple outer kernel with yellow embryo.
Wu was searching for such rare kernels — far less than one in 100 — that had two different fathers as a way to assess cooperation between the embryo and endosperm. “It was very challenging and time-consuming research,” said Friedman. “It was like looking for a needle in a haystack, or in this case, a kernel in a silo.”
Endosperm — in the form of corn, rice, wheat and other crops — is critical to humans, providing about 70 percent of calories we consume annually worldwide. “The tissue in the seeds of flowering plants is what feeds the world,” said Friedman, who also directs the Arnold Arboretum at Harvard. “If flowering plants weren’t here, humans wouldn’t be here.”
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CU Women Climb One Spot To No. 21 In AP Top 25 Poll
Feb 4th
BOULDER – Following a Southern California split, the University of Colorado moved up one spot to No. 21 in the Associated Press Women’s Basketball Top 25 poll, released Monday.
Colorado, 16-5 overall and 5-5 in the Pac-12 Conference, received 162 points, down from 205 last week. All five of Colorado’s losses have been to ranked teams, including two each to Stanford and California ranked No. 7 or better at the time. Stanford and California remained at No. 4 and No. 6 respectively, while UCLA moved up one spot to No. 17.
The Buffaloes do have one top 10 win on their resume, a 70-66 win over then-No. 8 Louisville on Dec. 14. The Cardinals are currently ranked No. 11.
The Buffaloes have resided in the AP poll for the last eight weeks, reaching as high as No. 20 twice – Dec. 31 and Jan. 21. CU’s eight-week run in the AP poll is its longest since appearing in all 19 polls of the 2003-04 season.
The Buffaloes have a long history of rankings in the AP poll, dating back to the 1980-81 season. This week’s ranking marks the 166th time Colorado has appeared in the AP poll, trailing only Stanford, USC and UCLA among Pac-12 schools.
The USA Today Sports Coaches poll is scheduled to be released on Tuesday. Colorado was No. 23 in last week’s coaches’ poll.
Colorado returns home for the first time in three weeks as the Buffaloes will host the Oregon schools. Colorado will face Oregon State on Friday, Feb. 8, at 7 p.m. and host Oregon on Sunday, Feb. 10, at 1:30 p.m. The Oregon State game will be televised by the Pac-12 Mountain Network while the Oregon game will be streamed live on Pac-12.com.
2012-13 Associated Press
Top 25 Poll – Feb. 4
Rk Team Rec Pts Last
1 Baylor (37) 20-1 997 1
2 Notre Dame 20-1 955 2
3 Connecticut (3) 20-1 928 3
4 Stanford 20-2 862 4
5 Duke 20-1 845 5
6 California 19-2 807 6
7 Maryland 18-3 753 10
8 Penn State 17-3 642 7
9 Georgia 19-3 632 13
10 Kentucky 19-3 630 8
11 Louisville 19-4 553 12
12 Tennessee 17-5 512 9
13 Purdue 18-3 502 14
14 Texas A&M 17-5 497 16
15 South Carolina 19-3 480 15
16 North Carolina 20-3 458 11
17 UCLA 17-4 409 18
18 Dayton 19-1 397 17
19 Florida State 18-4 223 20
20 Delaware 18-3 205 25
21 COLORADO 16-5 162 22
22 Oklahoma State 15-5 128 19
23 Oklahoma 16-5 127 21
24 Syracuse 18-3 80 NR
25 Iowa State 15-5 71 23
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Strong Second Half Pushes CU Women Past USC Trojans, 65-49
Feb 3rd
It’s been a tough road trip for the No. 22 Colorado women’s basketball team, with three straight road losses against nationally ranked opponents in the past two weekends.
On Sunday, though, the CU women had one last chance to pull out a road win over the Southern California Trojans — and this time, they made it happen.
Arielle Roberson was high scorer with 15 points
With a solid second-half effort on both sides of the ball, Colorado pulled away from the Trojans for a 65-49 victory.
“I really liked our toughness in this game,” said Colorado head coach Linda Lappe. “We didn’t have any of that on Friday, and so it was nice to kind of get our identity back because that’s who were are when we’re playing our best.”
It was a success that came at a much-needed time, as the Buffs were in the midst of their longest losing streak of the season. After falling to top-10 teams Cal and Stanford last weekend, Colorado shot less than 30 percent from the field in a 62-46 loss to No. 18 UCLA on Friday.
“I think we knew we could definitely win this game and that we had to win this game,” said redshirt freshman forward Arielle Roberson, who led the Buffs in scoring with 16. “We just knew we had to do it in a fun way and not make it too stressful.”
The stress was certainly still there in the first half, as the Buffs and Trojans traded baskets and both teams struggled to gain a solid advantage. The lead changed eight times throughout the half, and neither team went up by more than five.
In the four minutes before intermission, however, USC found its momentum and went on a 13-3 run to reverse Colorado’s five-point lead to a five-point lead of its own by halftime (31-26).
The Buffs shot 36 percent from the field in the first half compared to USC’s 33, but the Trojans were efficient from the line with an free throw percentage of 89.
Colorado, though, took control at the start of the second half, going on an 8-0 run and forcing five turnovers in the process to build a three-point lead.
“I kind of had a feeling that (the Trojans) were going to get tired in the second half,” Lappe said. “And I think that’s what happened. I think we pushed the ball really well at them in the first half, we were physical with them in the first half, and I think that wore on them in the second half.”
With 12:17 remaining, Roberson knocked down an “and-1” play to put the Buffs up eight (41-33). Four minutes later, senior guard Chucky Jeffery scored on a steal and a fast break to give CU a 10-point lead.
In the final two minutes, Colorado went on an 8-1 run capped by a Roberson trey and a Jeffery free throw, erasing USC’s chance for a late-game comeback.
By the final buzzer, the Buffs had gone up 16 for a 65-49 victory.
Lappe said the improvement her team made from Friday night’s struggle to Sunday’s success was indicative of a high-level team.
“Everybody has a bad game, championship teams have bad games,” Lappe said. “But the real championship teams respond in a great fashion. They can let it go, they can take it for what it’s worth, and they can get a little mad and come back even stronger. I think that’s what’s going to happen to us after that Friday night game.”
Colorado demonstrated its depth in both scoring and rebounding on Sunday, with four players scoring in double figures and six players grabbing five or more boards.
In addition to Roberson’s game-high 16 points, Jeffery scored 15 and grabbed 10 rebounds in the process for her fifth double-double of the season. Junior guard Brittany Wilson added 12 points, while sophomore guard Lexy Kresl scored 11 and grabbed six rebounds.
Overall, the Buffs out-rebounded the Trojans 44-29, with 13 of those on the offensive end. Colorado ended the game shooting 40.4 percent from the field, holding USC to just 27.5 percent.
Junior forward Cassie Harberts led the Trojans in scoring with 14 total points, below her average of 18.7, while sophomore guard Ariya Crook added 10.
The win bumps Colorado’s record to 16-5 overall and 5-5 in the Pac-12 Conference, while USC falls to 8-13 and 5-5 in conference play. The Trojans remain unsuccessful against ranked teams (0-6) so far this season.
Though the Buffs may be only .500 in conference play, their start to the season has been far from smooth sailing. Half of Colorado’s matchups so far in conference play have been against nationally ranked opponents, and four of those have been against top-10 Cal and Stanford teams.
Only one of Colorado’s next eight opponents, Washington, currently has a better record than the Buffs in the Pac-12.
The CU women return to the Coors Events Center next week with matchups against Oregon State on Friday and Oregon on Sunday.
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