Presentation of Selected Reading Plant Biology Paper

1. Populus cathayana
--Intra- and inter-sexual
competition under different
watering conditions
Presenter: Minyi Chen
Original authors: Juan Chen, Baoli Duan, Maolin Wang, Helena Korpelainen
and Chunyang Li

2. Populus cathayana
 Characteristics:
 30m high, broadly ovoid leaf, 800-3200 altitude
 Dioecious. Male flower catkin 5-6cm, 30-35 stamens
Female catkin 4-5cm, fruit 10-20cm (May-Jul)
 Phylogenetic classification
Kingdom Plantae
Phylum Magnoliophyta (binomial)/ Angiospermae (Engler [1])
Class Magnoliopsida /Dicotyledoneae (Engler)
Order Malpighiales / Salicales (Engler)
Family Salicaceae
Genus Populus
Species P. cathayana
(4 more variants)
(Figures from: PlantPhote.Cn)

3. Materials and methods
 60 males and 60 females ---- one year pre-cultured under optimal condition
from 15 different populations
 Condition ---- Spring, Qinghai Province, P.R.China
 Experiment setting ---- 10 weeks growth; water rewatered and weighted
every other day; 15N isotope and K source fertilized.
 Control factor (6 group with 1 vs 1 comparison, 10 repeats) ----
 Water: Well-watered (100% field capacity, 48.27% water weight),
Drought (30% field capacity, 14.48% water weight)
 Competition & sexual (1 vs 1): FF ; FM and MM
 Determination ---- Dry mass, 13C and N composition, Gas exchange
(Photosynthesis); Leaf water, Leaf sections (Electron microscopy); 15N
isotope labeled NH4
+ and NO3
- trace.
 Statistical analysis ---- Analysis of variance (one way and three ways
ANOVA), independent-sample t-test (sexual)

4. Results-- Biomass

5. Result-- Photosynthesis
 P max ---- light-saturated photosynthetic rates
 Photosynthetic nitrogen-use efficiency (PNUE) ---- P max per leaf N content

6. Result–
13C, N & 15N
 13C & N-- indicates long-
term water-use
efficiency
 15N -- NH4
+ trace is
higher efficient than
NO3
- trace when
suffering drought

7. Result-- Water
 Water potential
 Water-use efficiency (WUEi)--- ratio of Pn to Gs .

8. Result--- Leaf section
 Female did worse than male under dry conditions
Degradation in growth related organelles and increase in plastoglobules (P)
a) F/FM ---W b) M/FM ---W c) F/FM ---D d) M/FM ---D e ) F/FF ---D f) M/MM ---D
P
P
P
P
P
P
P
P
P

9. Conclusion--- Fitness
 Sexual (F have higher fitness than M in well-watered condition)
 F > M in intersexual (FM) condition
 FF = FM and MM = FM no fitness difference due to growth with
different sex
 Drought
 FF < MM F fit less in dry conditions than M (without intersexual
competition)
 F decreased roots and increased leaf biomass --- increasing their
light capture ability. M do opposite to adapt to bad conditions
 F/FM > F/FF F still do better when compete with M than with F
 F increase fitness and M decrease fitness when dry
 M may spare water for F when drought

10. Other studies and future apply
 More future studies:
 What is the difference between M and F in water conservation
mechanism?
 How male support water for female?
 Other recent studies:
 The tolerance to low O2 level [4] ---- treating eutrophic water
system
 Highly genetic diversity [5] ---- strong adaption to bad
environment
 Ability production by branch cutting method[6]
 Higher growth ability than other Populus species [7]

11. Acknowledgements
 [1] Zhao, Shi-dong (赵士洞). 1999. Flora of China. Science Press (Beijing) & Missouri Botanical
Garden (St. Louis). Vol 4(2)
 [2] Engler, A. 1982. Syllabus der Vorlesungen über specielle und medicinisch-
pharmaceutische Botanik: eine Übersicht über das Pflanzensystem mit Berücksichtigung
der Medicinal- und Nutzpflanzen, Gebrüder Borntraeger Verlag, Berlin
 [3] Taiz/Zeiger (1991). Plant Physiology. Redwood City, CA: The Benjamin/Cummings
Publishing Company, Inc. pp. 92–95.
 [4]李艳蔷, 张业阔, 宛晶, 席颖, 李兆华. “低氧富营养化水体中垂柳和青杨叶片生理指标的变化”.
Jiangsu Agricultural Sciences. 2012. (1)
 [5] 李宽钰, 黄敏仁, 王明庥, 杨自湘, 黄丰厚. “青杨的DNA多态性及遗传分化——Ⅰ.青杨的DNA多态
性”. Chinese Science Bulletin. 1997. (9)
 [6] FANG Yuemei, JIANG Peng, SHANG Lei, LU Guiqiao, GU Jiancai. Study of the stand
growth and growing period of P .cathayana by cutting breeding. Hebei Journal of Forestry
and Orchard Research. 2013, (3)
 [7] 方月梅. “不同繁殖方式造林对坝上杨树生长的影响”. Agricultural University of Hebei. 2013

12. Result-- Gas Exchange
 Net photosynthetic rate (Pn )
 Stomatal conductance (Gs ) [3]
 Transpiration rate (E)
Backup Slide

13. Backup Slide
P value Competition Sex +
watering
Sex +
competition
Watering +
competition
Sex + watering
+ competition
Leaf DMA + + + + -
Root DMA + + + + +
Shoot DMA + + + + +
Total DMA + + + + +
Root/shoot ratio + + - - -
Specific leaf area - + + + -
Pn - + + + +
Gs + + + + +
E + + + + +
Pmax - + + - -
PNUE - + + + -
Leaf N content - - - + +
Water potential - + + - +
𝛿13C + + + + -
WUEi - - - - -
15NO3
- - N - + + + +
15NH4
+ - N - - + - +