Populus cathayana--Intra- and inter-sexual competition under different watering conditions

Presenter: Minyi ChenOriginal authors: Juan Chen, Baoli Duan, Maolin Wang, Helena Korpelainen

and Chunyang Li

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)

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)

Results-- Biomass

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

Result– 13C, N & 15N

13C & N-- indicates long-term water-use efficiency

15N -- NH4+ trace is

higher efficient than NO3

- trace when suffering drought

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

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

PP

PP

P

P

P

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

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]

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

Result-- Gas Exchange Net photosynthetic rate (Pn ) Stomatal conductance (Gs ) [3]

Transpiration rate (E)

Backup Slide

Backup SlideP value Competition Sex +

wateringSex +

competitionWatering + 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 - - + - +