Costus pulverulentus (Costaceae) J. Antonio Guzmn Q. Programa - - PowerPoint PPT Presentation

Why do plants present heterophylly?: The case of the leaf functional traits of Costus pulverulentus (Costaceae)

• J. Antonio Guzmán Q.

Programa Regional de Posgrado en Biología, Sistema de Estudios de Posgrado, Universidad de Costa Rica. antguz06@gmailcom ATBC 2013

Phenomenon of heterophylly

“Changes in leaf size and shape along the axis

• f the individual (Winn 1999)”
• Derives from genetic control or their

plasticity

• Possible “strategy” t0 acclimatization and

adaptation

Introduction

Introducción

Costus species

• Some species present

changes in leaf size

(Kirchoff & Rutishauser 1990)

• But these authors and

taxonomists do not describe as possible conditions of heterophylly

• 1. C. pulverulentus present heretophylly?
• 2. Which can be its adaptive value?

Study Questions

Study Questions

• CEEC Dr. Alvaro

Wille Trejos

• Wet Tropical

Forest

• Costus pulverulentus

Specie and site of study

Methods

• CEEC Dr. Alvaro

Wille Trejos

• Wet Tropical

Forest

• Costus pulverulentus

Specie and site of study

Methods

Methods

1 2 3

Leaf morphological analysis Changes along the crown Light capture efficiency

Methods

1 2 3

 First sample (n= 20)  Three leaves were selected:

• Upper
• Middle
• Lower

 Landmarcks (2 points) and Semilandmarcks (26 points)  Procrustes transformación  PCA and ANOVA

• 1. Leaf morphological

analysis

Methods

1 2 3

• 2. Changes along

the crown

 Second sample (n=30):

• Divergence angles
• Leaves areas
• Specific leaf area
• Leaf area relations

 Standardization of the position in the crown (First leaf = 0; Last leaf = 1)

𝑂𝑀𝑓 = 𝑂𝑀 − 1 𝑂𝑀𝑢 − 1

Methods

1 2 3

• 3. Light capture

efficiency

 Same second sample (n= 30)  Two leaves shape were selected:

• Top-shape
• Basal-shape

 Plant achitecture Pearcy & Yang (1996)  STAR (Duursma et al. 2012)

Results and Discussion

Leaf morphological analysis

• Fig. 1. PCA from the procrustes transformation

PC1: F2, 57 = 52.62, p <0.001 PC2: F2, 57 = 1.72, p = 0.18

Upper-crown Lower-crown Middle-crown

Results and Discussion

Thin plate splines

Upper-crown Middle-crown Lower-crown

• C. pulverulentus has heterophylly !!!

Top shape Basal shape

Leaf sheet Base and Apex

Results and Discussion

Changes along the crown

• Fig. 3. Divergence angle, leaf size

and specific leaf area along the crown

NLe

0.0 0.2 0.4 0.6 0.8 1.0

Divergence angle (deg)

50 100 150

r2 = 0.41 y = 92.90 - 214.72x + 180.48x2

NLe

0.0 0.2 0.4 0.6 0.8 1.0

LA (cm2)

100 200

r2=0.34 y = 90.26 + 298.51x - 306.10x2

NLe

0.0 0.2 0.4 0.6 0.8 1.0

SLA (cm2 g-1)

200 300 400

r2= 0.21 y = 270.71 - 142.61x + 164.77x2

LA = leaf area SLA =speficic leaf area NLe = Leaf number standardized

Results and Discussion

Relationships between leaf areas

• Fig. 4. Relations of total leaf area,

mean leaf area and leaf number LAT = Total leaf area LAM = Mean leaf area A: F1,29= 86.31, p< 0.001 B: F1,29= 5.57, p= 0.025 C: F1,29= 47.67, p< 0.001

Nº leaves

8 12 16 20 24

LAt (cm2)

1250 2500 3750

r2= 0.75 y = -673.68 + 185.31x

Nº leaves

8 12 16 20 24

LAm (cm2)

80 120 160 200

r2= 0.17 y = 83.22 + 3.57x

LAm (cm2)

80 120 160 200

LAt (cm2)

1250 2500 3750

r2= 0.63 y = -744.71 + 19.26x

A B C

Results and Discussion

Light capture efficient

• Fig. 5. STAR according to the type and

number of leaves F1,59= 90.48, p<0.001

Top shape Basal shape

Nº of leaves

8 12 16 20 24

STAR (m2 m-2)

0.30 0.35 0.40 0.45

Basal-shape Top-shape

Leaf Shape

Basal Top

STAR (m2 m-2)

0.0 0.1 0.2 0.3 0.4 0.5

a b

Results and Discussion

Light capture efficient

• Fig. 5. STAR according to the type and

number of leaves F1,59= 90.48, p<0.001

Top shape Basal shape

Nº of leaves

8 12 16 20 24

STAR (m2 m-2)

0.30 0.35 0.40 0.45

Basal-shape Top-shape

Leaf length (cm)

10

LA (cm2)

0.1 1 10 Basal-shape Top-shape

Results and Discussion

Why have a basal morphology if top morphology is more efficient?

“This result might be the responsible for the production of basal leaf morphologies in early plant development”

• Fig. 6. Relationship between leaf length

and leaf area

• C. pulverulentus has heterophylly
• Mid-crown has a greater space utilization for

resource acquisition

• To increase leaf area the plant increases leaf

size

• Adaptation to minimize self-shading

Conclusions

The case of C. pulverulentus

• Coordinators of Biología de Campo Course

at UCR

• Roberto A. Cordero
• R. Duursma
• CEEC Dr. Alvaro Wille Trejos

Acknowledgment

Photo by R. Aguilar Thank you very much for your attention… PURA VIDA!!