ArticlePDF Available

Comparative morphological, epidermal, and anatomical studies of Pinus roxburghii needles at different altitudes in the North-West Indian Himalayas


Abstract and Figures

The aim of the present study was to understand the ecological adaptation of Pinus roxburghii Sarg. in the North-West Himalayan region. P. roxburghii needles showed morphological, epidermal, and anatomical variation at different altitudes. Needle length was negatively correlated with altitude. Stomatal characters like stomatal density, stomatal index, and guard cell lengths were found to be affected by environmental factors and showed a direct correlation with altitude. The results showed that potential conductance index was dependent on the climatic conditions of the habitat. The anatomical properties of needles exhibited variation from lower to higher elevation, especially in the number and position of resin ducts.
Content may be subject to copyright.
Turkish Journal of Botany
Turk J Bot
(2013) 37: 65-73
Comparative morphological, epidermal, and anatomical studies of Pinus roxburghii
needles at dierent altitudes in the North-West Indian Himalayas
Satyendra Prakash TIWARI*, Pradeep KUMAR, Deepika YADAV, Devendra Kumar CHAUHAN
Sahni Palaeobotany Laboratory, Department of Botany, University of Allahabad, Allahabad, India
* Correspondence:
1. Introduction
Chir pine (Pinus roxburghii Sarg.) is the dominant tree species
in the North-West region of the Indian Himalayas. It is a
hard pine of lower elevation, occurring between altitudes of
500 and 2500 m and is extensively distributed from Bhutan
to Afghanistan. Chir pine grows gregariously, oen forming
pure formation in xerophytic and well-lit environments
(Mehra, 1988). P. roxburghii is an economically valuable
species, balancing the ecosystem of the Indian mountains.
e plants show microhabitat-related morphological and
anatomical features at dierent altitudes.
Körner (2007) proposed the altitude-related theory
of biological phenomenon, which adversely aected the
plant communities like reduction in plant species number
(Nagy, 2003), plant productivity (Luo et al., 2004), body
or organ size trends (Fabbro & Körner, 2004), plant
physiology and morphology (Hoch & Körner, 2003), gene
ecology (Reisch et al., 2005), and life history characteristics
(Klimes, 2003).
Leaf traits are oen aected by the ecosystem’s
characteristics, as they are directly exposed to the
environment. In vascular plants the stomata of leaves
are the most important physiological apparatus for
photosynthesis and transpiration. e development
of stomata (about 400 million years ago) is therefore
considered a key event in the evolution of advanced land
plants (Hetherington & Woodward, 2003). Stomatal
dierentiation and development are determined by genetic
factors (He et al., 1998). Stomatal initiation is controlled
by the CO2 HIC gene, setting stomatal number during
leaf formation (Gray et al., 2000). Stomatal parameters are
specic for a particular species but are aected by multiple
ecological factors, including altitude gradient (Beerling
& Kelly, 1996), atmospheric CO2 concentration (Van de
Water et al., 1994), temperature, light, and irradiance
(Lockheart et al., 1998). Environmental eects on stomatal
density, stomatal conductance, and stomatal index have
been widely studied in living as well as in fossil plants
(Woodward & Bazzaz, 1988; Royer et al., 2001; Kouwenberg
et al., 2003). δ13 C and stomatal density are popular tools
for determining palaeoatmospheric CO2 level (Beerling et
al., 1995). Morphological and anatomical features of Pinus
needles also depend on abiotic factors (Fahn & Bemayoun,
1976; Schoettle & Rochelle, 2000). Physical factors like
growth, altitude, decrease in air temperature, atmospheric
pressure, increasing precipitation, and wind velocity aect
plant growth (Friend & Woodward, 1990; Körner, 2007). At
very high elevation sites severe environmental conditions
become severe for plant development and growth. In the
present study we describe morphological, epidermal,
and anatomical variations observed in the needles of P.
roxburghii growing at dierent altitudes. e paper also
mentions ecological adaptation adopted by P. roxburghii
plants in response to stressed environmental conditions.
Abstract: e aim of the present study was to understand the ecological adaptation of Pinus roxburghii Sarg. in the North-West
Himalayan region. P. roxburghii needles showed morphological, epidermal, and anatomical variation at dierent altitudes. Needle length
was negatively correlated with altitude. Stomatal characters like stomatal density, stomatal index, and guard cell lengths were found to
be aected by environmental factors and showed a direct correlation with altitude. e results showed that potential conductance index
was dependent on the climatic conditions of the habitat. e anatomical properties of needles exhibited variation from lower to higher
elevation, especially in the number and position of resin ducts.
Key words: Ecological adaptation, Pinus, resin duct, stomatal density, stomatal index
Received: 01.10.2011 Accepted: 11.09.2012 Published Online: 26.12.2012 Printed: 22.01.2013
Research Article
TIWARI et al. / Turk J Bot
2. Materials and methods
Needles of P. roxburghii were collected from 3 dierent
altitudes (1215, 1350, and 1775 m) in the Kumaun region.
e Kumaun Mountains occupy the central sector of the
Himalayas from lat 28°44 to 30°49N and long 78°45 to
81°1E (Figure 1). is vast region has variable topography,
climate, soil, and vegetation. Besides the mountainous
forms, needles of the same species were collected from a
plant growing in the Department of Botany, University
of Allahabad, Allahabad, Uttar Pradesh, India. Allahabad
is situated in the upper Gangetic Plain of India. All the
climatic datasets of dierent altitudes were obtained from
the Indian Meteorological Department, New Delhi (Table
1). For the purpose of this study 5 trees were selected at
each site (98, 1215, 1350, and 1775 m). irty needles were
selected from well-grown shoots of each tree.
For morphological observations 20 needles were
randomly selected from each tree. e length was
measured by the conventional method. Micro-slides
were prepared by traditional methods and the technique
proposed by Eo (2012). Transverse sections were stained
with a combination of Safranin and Fastgreen (Johansen,
1940). All microscopic slides were examined under a
light microscope (Olympus CH20i) and electronic image
Figure 1. Location map showing plant collection site.
Table 1. Climatic dataset from all 4 elevations showing temperature, average rainfall, and relative humidity.
Altitude (m) Temperature (°C) Rainfall average (mm) Relative humidity (%)
Max (mean) Min (mean)
98 32.55 21.25 80.42 70
1215 28.27 15.22 648 85
1350 28.55 15.22 659 85
1775 25.62 12.35 1152 90
Temperature (maximum and minimum means of centigrade), average rainfall (millimetres), relative humidity (percentage).
ʹ38ʹ43° 28ʹ38ʹ43°
TIWARI et al. / Turk J Bot
analysis equipment (Leica DM 2500 and Motic 2.0 Image
Stomatal parameters, like guard cell lengths of 15
stomata, were measured at 40× (resolution 648 × 486, 1296 ×
97) from each of the needles from all 4 elevations. Stomatal
density was determined by the method of Hultine and
Marshall (2001). irty needles were selected randomly for
the stomatal count. e epidermis of the leaf was separated
by maceration and stomatal count made from the middle
part of the needles at 10× and 20× with the help of a Motic
2.0 Image Plus camera. e stomatal density, stomatal index,
and potential conductance index were calculated with the
help of the formulae given below as equations 1–3:
SD = SC/NL × NW ........................................................... (1)
SI = SC × 100/SC + nEC .............................................. (2)
PCI = (guard cell length)2 × SD × 10–4 ....................... (3)
PCI = Potential conductance index, SD = Stomatal
density, SI = Stomatal index SC = Stomatal counts, NL
= needle length, Nw = needle width, nEC = number of
epidermal cells.
All the statistical analysis was performed with the help
of SPSS v. 10.0 and STATISTICA 11 soware; graphs were
prepared using Origin 6.1.
3. Results
3.1. Morphological analysis
In this study, the needle morphology of Pinus roxburghii
was aected by the altitude gradient. Length of needles
from dierent elevations was measured and the needle
length was negatively correlated (r = 0.9635, P = 0.0364)
with altitude. Needle length at 98 m (NL= 29.98 cm) was
2 times greater than that at 1775 m (NL= 15.14 cm) (Table
2). Needle length was less variable at medium elevation,
showing about 15% decrease from 1215 m to 1350 m
compared to that of lower to higher elevation (20% needle
length decrease from 98 m to 1215 m, 24% decrease from
1350 m to 1775 m).
3.2. Epidermal analysis
Epidermis of Pinus roxburghii needles showed highly
contrasting characters at dierent elevations. e distance
between 2 stomatal rows signicantly decreased in needles
of plants from lower to high altitudes. At an elevation of
98 m the needles showed 13.61 rows of nonstomatiferous
cells, which decreased to 4.80 rows of nonstomatiferous
cells at an elevation of 1775 m. It was highly correlated (r
= 0.9815) with altitude. Stomatal density increased due to
decreases in the number of nonstomatiferous rows, as they
are inversely correlated to each other. Stomatal density
showed a positive correlation (r = 0.8284, P = 0.1716) with
altitude (Figure 2). Stomatal density increased 59.46%
from lower altitude to higher altitude. Stomatal index also
showed a positive correlation (r = 0.8689, P = 0.1310) with
altitude. e length of guard cells in needles of P. roxburghii
was also aected by a change in elevation and it increased
with altitude (Figure 3). Stomatal conductance depended
on both stomatal density and size of stomatal aperture
(Holland & Richardson, 2009). Potential conductance
index was also measured and found to be signicantly
correlated (r = 0.8637, P = 0.1365) with altitude.
3.3. Anatomical analysis
Anatomical characters of Pinus roxburghii needles varied
with altitude. Transverse sections of needles from all
4 sites were studied. ey showed a thick cuticle and
well-developed mesophyll tissue. e hypodermis was
commonly 2–4 layered, showing less variation at 98, 1215,
and 1350 m altitudes but showing much variation at higher
elevations. e layer of hypodermis decreased and became
single layered (Figure 4). As P. roxburghii is a hard pine,
the vascular bundles numbered 2 and were situated close
to each other, but needles from higher elevations showed
vascular bundles located opposite each other.
Table 2. Variations in stomatal density, stomatal index, nonstomatiferous cells, needle length, potential conduct index, guard cell length,
position of resin duct, and number of resin ducts.
Stomatal density
(mean ± SD)
NSCs between
stomata (mean)
Nl (cm)
mean ± SD PCI
Guard cell
length (µm)
mean ± SD
Position of
resin duct
Number of
resin ducts
98 29.0 ± 2.127 4.208 13.614 29.98 ± 3.511 4.30 38.51 ± 2.444 EX 3
1215 37.75 ± 4.632 6.404 9.266 23.70 ± 2.101 7.71 45.22 ± 3.234 EX, SM 0, 1, 2
1350 43.40 ± 6.707 7.451 7.466 20.15 ± 1.889 9.57 46.96 ± 2.593 EX, M 2
1775 71.55 ± 8.140 12.451 4.800 15.14 ± 0.900 17.71 49.76 ± 2.351 M, ED 3
Stomatal density and guard cell length (data are mean of 15 replicates and standard deviation); NSC: Nonstomatiferous cells; Nl: Needle
length; PCI: Potential conduct index.
TIWARI et al. / Turk J Bot
Pinus roxburghii had 2–3 resin ducts per needle,
situated medianly and externally. At lower elevation (98
m) needles showed 3 resin ducts placed externally (Figure
4). At higher altitude (1215 m) the number of resin ducts
varied from 0 to 2. ese were situated slightly medianly
and externally. Needles of plants at 1350 m altitude had
2 resin ducts, placed medianly and slightly externally. At
higher elevation (1775 m), resin ducts numbered 3 but
were endonal in position (Figure 4), being just the opposite
of those at the lower elevation.
4. Discussion
ere are complex ecological factors aecting plant growth
at dierent altitudes, especially conifers, which are present
over a range of elevated regions in the world. Altitude
plays an important role in changing the physical factors,
decreasing total atmospheric pressure, and reducing
atmospheric temperature with implications for ambient
humidity (annual temperature decreases with elevation by
about 6.5 °C per km), increasing radiation under a cloudy
sky because of reduction in turbidity and a high fraction of
radiation at any given total radiation (Körner, 2007).
Changes in epidermis structure in needles are an eco-
physiochemical process. Environmental factors show a
direct response on stomatal pattern in the epidermis of
needles in the Kumaun Mountains. Epidermal features
such as stomatal density, stomatal index, guard cell length,
and potential conductance index (PCI) vary with altitudes.
e present study shows that stomatal parameters play a
signicant role in the adjustment of plants at dierent
altitudes. Stomatal arrangement responds to light intensity;
an increase in light intensity results in an increase in stomatal
index (Coupe et al., 2006). P. roxburghii, which grows on
the eastward slopes of the Kumaun Mountains, receives
more light intensity and light period than plants growing
on the westward slopes. e stomata of P. roxburghii are
more aected by the light intensity. Körner (1988, 1999)
suggested that the elevation changes the stomatal density
due to the eect of foliar light interruption. In the case of
the rst type of mountains, insulation increases at higher
elevation because shorter atmospheric path length reduces
scattering and absorption. In the case of the second type
of mountains, the frequency of cloud immersion increases
with elevation and insulation decreases with elevation.
e rst described mountains show stomatal density that
typically increases with elevation due to less scattering
of light or a higher transpiration rate. e North-West
Himalayan mountainous region has diverse topography;
it is considered the rst type of mountain system because
Figure 2. A- Negative correlation between needle length and altitude. B- Correlation between stomatal density (SD) and altitude.
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Needle length (cm)
Altitude (m)
r = 0.9635
0 200 400 600 800 1000 1200 1400 1600 1800
Stomatal density (pore/mm
Altitude (m)
r = 0.8284
0 200 400 600 800 1000 1200 1400 1600 1800
Guard cell length (µm)
Altitude (m)
r = 0.9965
Figure 3. Correlation between guard cell length of stomata and
TIWARI et al. / Turk J Bot
the stomatal density of P. roxburghii increases with
altitude. Stomatal density is the major measure that
indicates gaseous changes. According to Woodward
(1987), stomatal density and stomatal index decrease with
increasing atmospheric CO2 level both in geological time
and under laboratory conditions. It is reported that CO2
can directly aect stomatal dierentiation (Lockheart et
al., 1998) and that stomatal density is negatively correlated
with atmospheric CO2 below 3000 m (Qiang et al., 2003)
because CO2 level decreases with increasing elevation.
Previous studies have shown increases in stomatal
density, with elevation acting as a limiting factor in
photosynthesis. Increases in stomatal density resulting in
increasing stomatal conductance should oset the decreases
in pCO2, but it is reported that such CO2 availability is
not a limiting factor (McElvain, 2004). Stomatal density
10 µm
10 µm
10 µm 10 µm
Figure 4. Transverse section of Pinus roxburghii needles. A- Needle section at 98 m, showing 3 external resin ducts, B- Needle section at
1215 m, resin duct absent, C- Needle section at 1350 m, 2 external resin ducts, D- Needle section at 1775 m, 3 resin ducts 1 medial and
2 endonal in position, E- Structure of a resin duct, F- External resin duct, G- Medial resin duct, H- Endonal resin duct.
Abbreviations: EC = epithelial cell, SC = sheath cell, MC = mesophyll cell, L = lumen of resin duct, scale bar = 10 µm.
TIWARI et al. / Turk J Bot
and size are considered as eco-physiological parameters
because they conjugately inuence stomatal conductance.
According to Körner and Cochrane (1985), stomatal
density did not reect variations in stomatal conductance
under an integrated inuence of specic environment
at higher altitude. Guard cell length in needles of P.
roxburghii increases with altitude. Potential conductance
index is signicantly correlated from all elevation sites
because stomata at higher altitude were not open entirely
under severe environmental conditions such as low
temperature and irradiation. Enhanced UV-B radiation at
higher altitude limits stomatal opening normally and leads
to decreases in stomatal conductance, but in the present
study potential conductance index increased with altitude.
Stomatal conductance might be constrained at higher
altitude by low air and soil temperatures because they
inhibit stem sap ow, which increases the water potential
gradient and induces partial stomatal closure, leading to
decreased stomatal conductance. Water availability is an
important factor from lower altitudes to higher altitudes
that aects stomatal size and stomatal conductance.
Stomatal traits change with elevation due to response of
water availability rather than CO2 signicance (Beerling &
Kelly, 1996). Stomatal characters are modied by climatic
changes, which is also a signicant nding in the present
In the present study, Pinus roxburghii showed
morphological traits negatively correlated with altitude.
Length of needle decreased with higher elevations. Eect
of altitude on morphology has been studied in Pinus
sylvestris L. (James et al., 1994), Pinus pumila Regel.
(Kajimoto, 1993), and Pinus contorta Douglas ex Louden
(Schoettle, 1990). ey all have shown reduced leaf length,
shoot growth, and leaf production per year with increasing
elevation. Leaf structure is modied according to need in
nature. Leaf morphology is aected by amount of δ13 C
and drought. Generally air becomes drier with increasing
elevation, but the diusion coecient of water vapour in air
also increases at higher elevation; both phenomena aect
the needle’s morphology. A sharp increase in needles’ δ13 C
suggested a strong capacity for CO2 assimilation, resulting
in rapid plant growth. Length of needles also varies due
to other environmental gradients like seasonal variation
(Armstrong et al., 1988) and temperature. e present
study reveals that the length of P. roxburghii needles is
sensitive to the limiting factors in any given environment
and shows morphological changes.
Anatomical properties like leaf structure, leaf shape,
and cell distribution also change together with leaf
function for adaptation to severe ecological conditions.
Chir pine needles from all 4 elevation sites showed
interesting anatomical variation. Epidermal cells were
smaller and narrower in plants at higher elevation sites
than in those at lower elevation. Number of hypodermal
cell layers decreased from lower to higher altitudes.
e mesophyll cells showed a similar arrangement but
dierentiation in size because CO2 concentration aected
mesophyll cell structure and development (Lin et al.,
2001). Leaf thickness increased due to well-developed
mesophyll tissue. Elevation also aected light intensity,
because the photosynthetic rate changed. Needle anatomy
is also inuenced by soil resource enrichment or nutrient
availability in soil.
Transverse sections of Pinus needles were cut to study
the structure and position of resin ducts. Resin ducts are
a characteristic feature of conifers, occurring in vascular
tissues and ground tissues of all plant organs. Resin ducts
are also useful in the identication of species. e role of
resin ducts in classication of Pinus is more appreciated
compared to other polyphyletic traits, which are oen
treated as ambiguous. In the resin duct of Pinus, the duct
cavity is surrounded by a thin layer of unliginied cells,
which are termed epithelial cells. Outside these are one or
more layers of cells with relatively thick unlignied walls,
termed sheath cells. In P. roxburghii, resin ducts have a
wide cavity, surrounding a layer of 6–7 thin and delicate
epithelial cells. e sheath cells may vary in number from
8 to 12 and have thick walls (Figure 4). According to Napp-
Zinn (1966) and Biswas and Johri (1997), 4 types of resin
ducts are present in the needles of Pinus: 1) ducts in contact
with the endodermis (i.e. endonal); 2) ducts in contact
with the hypodermis (i.e. external); 3) ducts present in the
middle of mesophyll layers (i.e. median); 4) ducts inside
the bundle sheath (i.e. septal) (Figure 4). Most Pinus
species contain 1 or 2 types of resin ducts in the needle.
Needles of P. roxburghii generally show 2–3 external or
medial resin ducts (septal resin duct is not seen) (Figure
4). Variation in the arrangement pattern of resin ducts
in P. roxburghii at dierent altitudes was studied here for
the rst time. e number of resin ducts, however, does
not vary from lower to higher elevation sites. e middle
elevation (1215, 1350 m) sites show much variation (0, 1,
2). e most signicant feature is the position of the resin
duct, which varied from external (98, 1215 m) to medial
(1215, 1350 m) to endonal (1775 m) at dierent elevations
(Figure 4). e number of resin canals in P. roxburghii is
controlled genetically because it does not vary in number
but variation is seen in the position of the mesophyll. e
change in position may be attributed to the change in
altitude gradient and climatic factors.
Variations in resin duct patterns and changes in
the number and size of mesophyll cells are reportedly
aected by altitude (Sheue et al., 2003). Variations in the
distribution and number of resin ducts in the plant body
TIWARI et al. / Turk J Bot
are also aected by several genetic and environmental
factors, such as height and age of the tree, nutrition,
sunlight, radiation, temperature, wind, freezing, re,
insect attack, and phytohormones (Helmers, 1943; Fahn
& Bemayoun, 1976). ere is no signicant change in the
number of resin ducts with increasing elevation. Matziris
(1984) reported that the number of resin ducts increases
with increasing latitude. e evolutionary signicance of
the number of resin ducts is not well understood, but the
relationship between them and the resistance of genotypes
to specic insect attack has been reported (Overhulsen
& Cara, 1981). us it is clear that altitude aects the
position and number of resin ducts. Physiochemical
changes adapted by plants may also have an eect but this
requires detailed study.
5. Conclusion
Pinus roxburghii, a common wild species of conifer in the
North-West Himalayan region, grows at a wide range of
altitudes. It is the principle resin-producing species in
India. e present study reveals that P. roxburghii is mainly
aected by the altitude gradient or climatic factors. Trees
native of lower elevations can be distinguished from trees of
higher elevations on the basis of epidermal, morphological,
and anatomical characters of needles. Stomatal density,
stomatal index, and potential conductance index
show signicant variation at dierent altitudes due to
environmental factors such as CO2 concentration, light
intensity, and water availability (Figure 5). Needle length
is also aected by ecological factors; they are signicantly
negatively correlated with altitudes. e most interesting
Figure 5. Array and distribution of stomata on epidermis of Pinus roxburghii needles. A- at 98 m height, B- at 1215 m height, C- at 1350
m height, D- at 1775 m height. Scale bar = 20 µm.
TIWARI et al. / Turk J Bot
feature shown, however, is the variation in the position of
the resin duct (external, medial, and endonal) at dierent
elevations, which is a genetically controlled characteristic
in plant parts. Trees at lower elevation, with external resin
ducts, can be distinguished from higher elevation trees,
having medial and endonal resin ducts. us, we can
conclude that altitude and environmental factors can aect
the physiochemical process of P. roxburghii in the Indian
Himalayan region.
e authors are highly grateful to Prof Nupur Bhowmik
for going through the manuscript and giving her advice
about completing this paper. We are indebted to the
Head of Department for providing laboratory facilities.
e authors are also thankful to Prof Manju Sahney for
her valuable suggestions and all other members of the
Palaeobotany and Morphology laboratory.
Armstrong JK, Williams K, Huenneke LF & Mooney HA (1988).
Topographic position eects on growth depression of
California (USA) Sierra Nevada pines during the 1982–1983 El
Nino. Arctic and Alpine Research 20: 352–357.
Beerling DJ, Birks HH & Woodward FI (1995). Rapid late-glacial
atmospheric CO2 changes reconstructed from the stomatal
density record of fossil leaves. Journal of Quaternary Sciences
10: 379384.
Beerling DJ & Kelly CK (1996). Evolutionary comparative analysis
of the relationship between leaf structure and function. New
Phytologist 134: 3551.
Biswas C & Johri BM (1997). e Gymnosperms. New York: Springer-
Coupe SA, Palmer BG, Lake JA, Overy SA, Oxborough K,
Woodward FI, Gray JE & Quick WP (2006). Systemic
signalling of environmental cues in Arabidopsis leaves. Journal
of Experimental Botany 57: 329–341.
Eo JK (2012). A simple technique for cross-sectioning Gymnosperm
needle leaves using microtome. Turkish Journal of Botany 36:
Fabbro T & Körner Ch (2004). Altitudinal dierences in ower traits
and reproductive allocation. Flora 199: 70–81.
Fahn A & Benayoun J (1976). Ultrastructure of resin ducts in Pinus
halepensis development, possible sites of resin synthesis, and
mode of its elimination from the protoplast. Annuals of Botany
40: 857–863.
Friend AD & Woodward FI (1990). Evolutionary and
ecophysiological responses of mountain plants to the growing
season environment. Advances in Ecological Research 20: 59–
Gray JE, Holroyd GH, van der Lee F, Sijmons PC, Woodward FI,
Schuch W & Hetherington AM (2000). HIC: a gene involved
in controlling stomatal development in responses to changes in
atmospheric CO2 concentration. Nature 408: 713–715.
Helmers AE (1943). Ecological anatomy of ponderosa pine needles.
e American Midland Naturalist 29: 55–71.
Hetherington AM & Woodward FI (2003). e role of stomata in
sensing and driving environmental change. Nature 424: 901–
Hoch G & Körner Ch (2003). e carbon charging of pines at the
climatic treeline: a global comparison. Oecologia 135: 10–21.
Holland N & Richardson AD (2009). Stomatal length correlates
with elevation of growth in four temperate species. Journal of
Sustainable Forestry 28: 63–73.
He X-Q, Lin Y-H & Lin J-X (1998). Research on correlation between
stomatal density and variation of atmospheric carbon dioxide
during a century. Chinese Science Bulletin 43: 860–862 (in
Hultine KR & Marshall JD (2001). A comparison of three methods
for determining the stomatal density of pine needles. Journal of
Experimental Botany 52: 369–373.
James JC, Grace J & Hoad SP (1994). Growth and photosynthesis
of Pinus sylvestris at its altitudinal limit in Scotland. Journal of
Ecology 82: 297–306.
Johansen DA (1940). Plant Microtechnique. New York: McGraw-Hill
Book Co.
Kajimoto T (1993). Shoot dynamics of Pinus pumila in relation to
altitudinal and wind exposure gradients on the Kiso mountain
range, central Japan. Tree Physiology 13: 41–53.
Klimes L (2003). Life-forms and clonality of vascular plants along an
altitudinal gradient in East Ladakh (NW Himalayas). Basic and
Applied Ecology 4: 317–328.
Körner C (1988). Does global increase of CO2 alter stomatal density?
Flora 181: 253–257.
Körner C (1999). Alpine Plant Life. Berlin: Springer-Verlag.
Körner C (2007). e use of ‘altitude’ in ecological research. Trends in
Ecology and Evolution 22: 11.
Körner C & Cochrane O (1985). Stomatal responses and water
relations of Eucalyptus pauciora in summer along an
elevational gradient. Oecologia 74: 443–445.
Kouwenberg LLR, McElwain JC, Kürschner WM, Wagner F, Beerling
DJ, Mayle FE & Visscher H (2003). Stomatal frequency
adjustment of four conifer species to historical changes in
atmospheric CO2. American Journal of Botany 90: 610–619.
Lin J, Jach ME & Ceulemans R (2001). Stomatal density and needle
anatomy of Scots pine (Pinus sylvestris) are aected by elevated
CO2. New Phytologist 150: 665–674.
TIWARI et al. / Turk J Bot
Lockheart MJ, Poole I, Van Bergen PF & Evershed RP (1998).
Leaf carbon isotope composition and stomatal characters:
important consideration for palaeoclimate reconstructions.
Organic Geochemistry 29: 1003–1008.
Luo TX, Pan Y, Ouyang H, Shi P, Luo J, Yu Z & Lu Q (2004). Leaf
area index and net primary productivity along subtropical to
alpine gradients in the Tibetan Plateau. Global Ecology and
Biogeography 13: 345–358.
McElwain JC (2004). Climate-independent paleoaltimetry using
stomatal density in fossil leaves as a proxy for CO2 partial
pressure. Geology 32: 1017–1020.
Matziris DI (1984). Genetic variation in morphological and
anatomical needle characteristic in the Black pine of
Peloponnesos. Silvae Genetica 33: 4–5.
Mehra PN (1988). Indian Conifer, Gnetophytes and Phylogeny of
Gymnosperms. New Delhi: Rajbandhu.
Nagy L, Grabherr G & Körner C (2003). Alpine biodiversity in space
and time: a synthesis. Alpine Biodiversity in Europe 167: 453–
Napp-Zinn K (1966). Anatomie des Blattes. I. Blattanatomie der
Gymnospermen. Berlin-Nikolassee: Gebrüdder Borntraeger.
Overhulsen D & Cara RI (1981). Occluded resin canals associated
with egg cavities made by shoot infecting Pissodes. Forest
Science 27: 297–298.
Qiang W, Wang X, Chen T, Feng H, An L, He Y & Wang G (2003).
Variations of stomatal density and carbon isotope values of
Picea crassifolia at dierent altitudes in the Qilian Mountains.
Tre es 17: 258–262.
Reisch C, Anke A & Rohl M (2005). Molecular variation within and
between ten populations of Primula farinosa (Primulaceae)
along an altitudinal gradient in the northern Alps. Basic of
Applied Ecology 6: 35–45.
Royer DL, Wing SL, Beerling DJ, Jolley DW, Koch PL, Hickey LJ &
Berner RA (2001). Paleobotanical evidence for near-present-
day levels of atmospheric CO2 during part of the Tertiary.
Science 292: 2310–2313.
Schoettle AW (1990). e interaction between leaf longevity and
shoot growth and foliar biomass per shoot in Pinus contorta at
two elevations. Tree Physiology 7: 209–214.
Schoettle AW & Rochelle SG (2000). Morphological variation of
Pinus exilis (Pinaceae), a bird-dispersed pine, across a range
of elevations. American Journal of Botany 87: 1797–1806.
Sheue CR, Yang YP & Huang LLK (2003). Altitudinal variation of
resin ducts in Pinus taiwanensis Hayata (Pinaceae) needles.
Botanical Bulletin Academia Sinica 44: 305–313.
Van de Water PK, Leavitt SW & Betancourt JL (1994). Trends in
stomatal density and 13C/12C ratio of Pinus exilis needles
during last glacial-interglacial cycle. Science 264: 239–243.
Woodward FI (1987). Stomatal numbers are sensitive to increases in
CO2 from pre-industrial levels. Nature 327: 617–618.
Woodward FI & Bazzaz FA (1988). e response of stomatal density
to CO2 partial pressure. Journal of Experimental Botany 39:
... Fraxinus. Las densidades estomáticas obtenidas en este estudio (61.03 estomas/mm²) para P. devoniana están dentro del intervalo reportado para el mismo género; con valores entre 29 y 71 estomas/mm² ( Pinus roxburghii) y 44 y 74 estomas/mm² (Pinus sylvestris) (Jinxing et al. 2001;Tiwari et al., 2013). ...
Full-text available
Mexico is the world's leading avocado producer, with 45% of global exports. Michoacán occupies the first place in avocado production in Mexico (86%), with approximately 200,000 hectares of avocado plantations. A large amount of this area has been established, replacing native forests, and the hydrological impact of this change in land use is still unknown. So, a question arises. How much water does Persea americana use compared to the main native tree species of forests in central Mexico? To answer this question, we compared water consumption between avocado (Persea americana var Hass) and two native species of the montane forests of central Mexico; Lacio pine (Pinus devoniana) and Mexican ash (Fraxinus uhdei). To do so, we performed a two-phase study. First, we calibrated Granier-type sap flow sensors (TDP) to estimate water consumption in saplings of the target species. And second, we performed sap flow measurements in saplings of the three species under semi-controlled field conditions. The results show that the original Granier equation (u = aK^b) with coefficients a=0.0119 and b=1.231 underestimated avocado’s sap flow by nearly 6 times and almost 5 times the sap flow of pines. In the case of ash trees, the original equation overestimated the sap flow by approximately 7 times. The coefficients obtained for pines (a= 0.102; b=1.465), ash trees (a= 0.002; b= 2.540), and avocados (a= 0.128; b= 1.874) through calibration allowed estimating water consumption that showed good agreement with the water consumption values estimated from gravimetrical measurements. After the calibration, we carried out a 122 days field experiment comprising the dry hot, wet (rainy), and dry-cold seasons in 2020 using saplings of the three species. As part of the experiment, we measured sap flow and meteorological variables in 10-minute intervals. Stomatal density and leaf area were also determined. The results indicate avocados' average transpiration depths were 0.38 ± 0.06 mm/day, with 0.07 ± 0.01 mm/day for ash trees and 0.06 ± 0.006 and mm/day for pines. All species showed a significant seasonal variation. Avocados consumed, on average, 6.3 and 5.4 times more water than pines and ash trees, respectively. The stomatal density analysis revealed that avocados had 495.6 ± 9.03 stomata per mm², while pines and ash trees had 61.03 ± 1.42 and 145.2 ± 2.29 stomata per mm². Stomata density explains why pine individuals with larger leaf areas transpire less water than avocados. Finally, Vapour Pressure Deficit was the meteorological variable that best explained transpiration in all species.
... A pesar de que no existe una relación clara entre las características de los estomas (Čortan & al. 2017(Čortan & al. , Zhang & al. 2017 y las condiciones ambientales, varios estudios demuestran el efecto de elevados niveles de iluminación y de ambientes secos sobre el incremento del número y densidad estomática en especies del género Pinus (Grill & al. 2004, López & al. 2008, Tiwari & al. 2013, Ghimire & al. 2014. En las arenas cuarcíticas con sílice se combinan ambas condiciones: alta reflexión de la luz determinada por las características físicas (color) del suelo y baja densidad del bosque que conduce a una mayor luminosidad; por tanto, esta pudiera ser la razón de los mayores números de estomas encontrados. ...
Full-text available
Los artículos de acceso abierto publicados en la Revista del Jardín Botánico Nacional se distribuyen según regulaciones de Creative Commons Attribution 4.0 International licence (CC BY 4.0-Variación anatómica foliar en poblaciones naturales de Pinus tropicalis en Pinar del Río, Cuba RESUMEN La variación de los caracteres anatómicos es crucial para evaluar la adaptabilidad ecológica, la cual reviste gran importancia para el manejo forestal y la conservación de especies endémicas. Pinus tropicalis es un árbol endémico distribuido por la provincia Pinar del Río y la Isla de la Juventud, Cuba. Ocupa gran variedad de ecótopos en poblaciones puras o en simpatría con P. caribaea var. caribaea. El objetivo de este estudio fue evaluar la variación anatómica de las acículas de P. tropicalis como respuesta diferencial adaptativa a las condiciones ambientales determinadas por la litología, la altitud y la pendiente. Se muestrearon de 20 a 30 individuos de todos los ecótopos donde crece la especie naturalmente. Se realizaron cortes transversales a 10 acículas de cada árbol y se evaluaron 12 variables anatómicas. Los resultados de los análisis estadísticos revelaron diferencias significativas entre individuos de los ecótopos, fundamentalmente en las arenas cuarcíticas con alto contenido de sílice. El análisis de componentes principales mostró una relación entre variables anatómicas relacionadas con la economía hídrica y la asimilación. El discriminante distinguió grupos definidos a partir de la relación de las variables anatómicas con la litología. Las variables que más contribuyeron a discriminar entre ecótopos fueron las relacionadas con la regulación hídrica, el número y diámetro de los canales de resina y el grosor de la cutícula. La disponibilidad de agua y la oligotrofia de los sustratos son los factores que más influyeron en la variación anatómica. Los resultados son una contribución a la ecología y la silvicultura de la especie. Palabras clave: adaptación, análisis multivariado, diferenciación anatómica ABSTRACT The variation of anatomical traits is crucial to assess ecological adaptability, which is of great importance for forest management and the conservation of endemic species. Pinus tropicalis is an endemic tree distributed in the province of Pinar del Río and Isla de la Juventud, Cuba. It occupies a great variety of ecotopes in continuous pure adaptability populations or in sympatry with Pinus caribaea var. caribaea. The objective of this study was to evaluate the anatomical variation of Pinus tropicalis needles as an adaptive differential response to environmental conditions determined by lithology, altitude and slope. Twenty to thirty individuals were sampled from all the ecotopes where the species grows naturally. Cross sections were made from 10 needles of each tree and 12 anatomical variables were evaluated. The results of the statistical analysis revealed significant differences between ecotopes, mainly in quartzite sands with high silica content. The principal component analysis showed a relationship between anatomical variables related to water economy and assimilation. The discriminant distinguished groups defined from the relationship of the anatomical variables with the lithology. The variables that contributed the most to discriminate between ecotopes were those related to water regulation, the number and diameter of the resin channels, and the thickness of the cuticle. The availability of water and the oligotrophic substrates are the factors that influence anatomical variation. The results are a contribution to ecology and silvicultural management of the species.
... The interpopulation variability of P. tabuliformis morpho-anatomical needle traits also showed a positive correlation between the needle size and the amount of annual precipitation (Zhang et al. 2017), in contrast to P. yunnanensis needle size that showed a negative correlation with the amount of annual precipitation and temperature but a positive correlation with the latitude (Huang et al. 2016). In Pinus roxburghii, the needle length was shorter at higher altitudes (Tiwari et al. 2013). ...
Interpopulation and intrapopulation variability of three morphological needle traits (length, width and thickness) was investigated in 16 natural silver fir populations in the Balkan Peninsula. The populations represent refugial areas of silver fir ( Abies alba Mill.). This paper aims to provide a comprehensive analysis of the influence of climatic factors (mean annual temperature, number of days with temperatures < 0, > 5, < 18, > 18<sup>o</sup>C, Hargreaves climatic moisture deficit and De Martonne aridity index, on the pattern of morphological needle traits within each population. Populations showed variation in the analyzed morphological needle traits, which could not be clearly defined by any of the analyzed climatic factors. The De Martonne aridity index and Hargreaves climatic moisture deficit had the greatest impact on the trait values, whereas the mean annual precipitation had the lowest. Evolutionary ecology research of the silver fir needle morphology is a valuable contribution to the comprehention of the present genetic variability as a prerequisite for adaptation to the rapid climate change and conservation of the species area in the Balkan Peninsula region.
... Because they are immediately exposed to the environment, leaf features are frequently influenced by ecosystem variables. The most significant physiological machinery for photosynthesis and transpiration in vascular plants is the stomata of leaves (Tiwari et al. 2013;Auclair 2014;Liu et al. 2019). ...
Full-text available
Damaiyani J, Fiqa AP, Rindyastuti R, Lestari DA, Rahadiantoro A, Yulistyarini T. 2022. Comparative anatomical study of leaves for twelve Indonesian woody plant species. Biodiversitas 23: 3744-3754. Foliar epidermal and stomatal features are widely used as plant microscopic traits either from taxonomic or ecological standpoints. The studies on woody plants in the Malesian region which serve as the essential component of tropical ecosystems are still limited. Here we conduct a comparative study on stomatal and epidermal features of twelve important woody plant species from Indonesia using a descriptive method based on the Light Microscope and Scanning Electron Microscope micrographs. The shape, size and stomatal type were revealed in all species studied. Moreover, quantitative features were measured including epidermal cell length and width, solidity (S), aspect ratio (AR), and stomatal index (SI). The study results showed a variation in foliar epidermal and stomatal traits across the species studied. Due to the presence of trichomes and waxes on the abaxial side, not all species can be measured for their stomatal index and epidermal cells. Syzygium polyanthum has the highest stomatal index and cells with complex interlocking shapes, which provide an effective strategy for reducing mechanical stress on epidermal cell walls, making this native species predicted to adapt well when it was planted in habitats with similar environmental conditions.
... It has been reported that stomatal characters such as stomatal density and stomatal index were found to be affected by environmental factors and showed a direct correlation with elevation (Tiwari et al. 2012). Moreover, differences in the number of stomata may depend on the habitat differences and leaf size, and thus stomatal indices change with respect to habitat, especially to microclimatic factors (Çakır & Bağcı 2006). ...
This paper comprehensively discusses anatomical features of the genus Tulipa (Liliaceae) in Turkey. These are compared with the current subgeneric classification. Anatomical structures, including transverse sections of the root, stem (scape) and leaf, and surface sections of the leaves are illustrated based on the 420 preparations obtained from 42 OTUs (populations) belonging to 18 taxa. Densities of stomata and epidermis cells per unit leaf area (mm2), stomatal index and ratio of stomata index on the leaf surfaces were also calculated. Cluster and principal component analyses (PCA) were employed, and all results were compared at the population level. In this anatomical study, some significant differences were found among Tulipa taxa, especially at the infrageneric and interspecific levels. The results of anatomical investigations are consistent with published results of previous morphological and molecular analyses. The results of cluster analysis and PCA support the classifications of Veldkamp & Zonneveld and Christenhusz et al. including three subgenera, Eriostemones, Tulipa and Clusianae, but subgenus Orithyia was not included in this study because it is absent from Turkey. Subgenus Eriostemones is divided into two sections, Sylvestres and Saxatiles, following treatments by Baker and Eker et al. In subgenus Tulipa, although morphometric analyses partially supported the taxonomic grouping previously proposed as three separate sections, Tulipa, Tulipanum and Eichleres, it also clearly indicates that considering them as a single section (Tulipa) is perhaps a better option.
... Although most of the morphological and anatomical traits of needles are more or less speci c for the species, the genetic investigations have demonstrated intraspecies genetic variations [16,17]. Adaptation of needle characteristics to the environment was also described [19][20][21][22][23], as well as microevolution within species and needle evolution by comparing morphology and anatomy [24][25][26][27]. Nagy et al. [28] proposed the theory of the altitude-related biological phenomenon, which has had negative effects on plant communities reducing the number of plant species [29], the plant productivity [30], the organ size trends [31], the physiology and morphology of plants [32], the gene ecology [33] and the characteristics of the history of life [34]. ...
Full-text available
The study of morphological and anatomical characteristics of leaves is important for assessing the geographical variation of species. The ecological adaptability of forty individuals from four populations of Cedrus atlantica were studied, based on analysis of morphological and anatomical traits. The results of the Spearman nonparametric coefficient of correlation showed that the number of stomatal lines (NLS) and the length of the needle (NL) are negatively correlated to altitude and positively to latitude and precipitation sums, while the width of the needle (NW), the thickness of the cuticle (CT), and the number of needles per rosette (NN/R) were negatively related to temperature. In addition, the sum of precipitation is negatively correlated with NW. The first two principal components account for 58.18% of the variation. According to Tukey’s test and Kruskal–Wallis test, all populations had at least three characters separating them at a statistically significant variation. Moreover, the hierarchical classification led us to the individualization of three main groups. All these results show an adaptation of the structure of the needles of C. atlantica from Morocco to the geographical position and the climatic conditions of the populations.
... Similarly, needle length of P. roxburghii Sarg. from the northwestern Indian Himalayas significantly correlated with altitude (Tiwari et al. 2013). Furthermore, differences in the morphological and anatomical properties of cones, needles and seeds along altitudinal and longitudinal gradients were reported in four populations of P. brutia Ten. by Dangasuk and Panetsos (2004). ...
In the present study, needle variation of Scots pine ( Pinus sylvestris L., Pinaceae) populations in Turkey was investigated. From selected eight populations, a total of 1314 needles belonging to 206 trees were examined. Four morphological needle traits were measured and analyzed to describe the population diversity and differentiation. Analyzed morphological traits showed significant variability. The trees within populations differ significantly in all analyzed needle characteristics, while the differences between populations were significant for the three of four studied characteristics. Present findings revealed that needle length, needle width and the ratio of needle length to needle width showed clinal variation in response to altitudinal gradients. Populations from higher altitudes were characterized with the smaller and wider needles as compared to the populations from lower altitudes. The results of this study could be valuable baseline data for the development of more efficient management plans for this forest tree species.
... ISSN 2410-5546 RNPS 2372 (DIGITAL) -ISSN 0253-5696 RNPS 0060 (IMPRESA) largo plazo afectará la supervivencia y el crecimiento de la planta (Grill & al. 2004, Huang & al. 2016). Variaciones en la morfología y la estructura anatómica de la acícula entre individuos y poblaciones obedece a diferencias en las condiciones de edátopo y los regímenes de humedad del hábitat donde crecen , Tiwari & al. 2013, Ghimire & al. 2014, Meng & al. 2018) y pueden ser usados como un método rápido para explorar la variación genética entre poblaciones (Boratyńska & al. 2015a, 2015b, Zhang & al. 2017. Las dimensiones y distribución de los tejidos en la anatomía de la acícula han sido estudiadas fundamentalmente para especies con amplios rangos de distribución (Boratyńska & al. 2015a, Jankowski & al. 2017, Köbölkuti & al. 2017) y ambientes contrastantes (Boratyńska & al. 2015a, 2015b, Hodžić & al. 2020. ...
Full-text available
Variation of anatomical characters is crucial in the recognition of ecological adaptability, especially in Pinus. Pinus caribaea var. caribaea is an endemic taxon of Western Cuba that grows in pure populations or sympatry with Pinus tropicalis and occupies a great variety of ecotopes that are also distinguished by the characteristics of the edatope. The objective of this research is to determine the anatomical variation of the needles as an adaptive differential response to the environmental conditions determined by lithology, altitude and slope. From 20 to 30 individuals from all the ecotopes where the taxon grows naturally were sampled. Cross sections were made of 10 needles from each tree and 12 anatomical variables, related to water regulation, transport and storage of metabolites, were assessed. The results of the statistical analysis revealed significant differences between ecotopes. The principal component analysis showed a relationship between anatomical variables that follow a functional pattern of water regulation and assimilation. The cluster and discriminant analysis made possible to distinguish the formation of groups by the relationship of the anatomical variables, mainly due to the effect of lithology, and those that contributed the most to differentiate them were those of water regulation, primary metabolism together with cuticle thickness. The results are a contribution to the local conservation of the taxon since the structure of the anatomical variation is a consequence of the genetic evolution of the populations and are very important in ecological and for silvicultural management. Citation: Geada-López, G., Sotolongo-Sospedra, R., Pérez-del Valle, L. & Ramírez-Hernández, R. 2021. Diferenciación anatómica foliar en poblaciones naturales de Pinus caribaea var. caribaea (Pinaceae) en Pinar del Río y Artemisa, Cuba. Revista Jard. Bot. Nac. Univ. Habana 42: 175-188. Received: 23 March 2021. Accepted: 13 May 2020. Online: 21 July 2021. Editor: José Angel García-Beltrán.
Plant functional traits are broadly used to quantify and predict impacts of climate change on vegetation. However, high intraspecific trait variation can bias mean values when few measurements are available. Here, we determine the extent of individual leaf trait variation and covariation across a highly heterogeneous environmental gradient for a widely distributed subtropical pine. We demonstrate the implications of trait variation for characterising species by assessing data availability and variability across the Pinus genus. Central Mountain Range, Taiwan. Pinus taiwanensis Hayata (Pinaceae). We measured eight functional traits suggested to reflect plant strategies: needle length, area, thickness, dry and fresh mass, stomatal row density (SD), leaf dry matter content (LDMC) and specific leaf area (SLA). We examined trait variation in response to climatic and physiographic factors across an elevational gradient of 495–3106 m a.s.l. using linear mixed effects models (LMMs). Intraspecific trait covariation was explored using principal component analyses (PCAs) and LMMs. Descriptive statistics were calculated for Pinus records in the global TRY plant trait database. Intraspecific variability among traits was high (CV 20%–44%) and predictable with elevation (generally p < 0.05, with declining needle size and LDMC with elevation and increasing SD). However, 41%–92% of variance was un‐explained by topography. Sixty‐five percent of variation was explained by two trait covariation axes, with predictable changes with elevation (p < 0.001). Pinus data availability in TRY was low. Across traits, only 12.5%–53% of species had sufficient sample sizes for intraspecific analyses. We show substantial trait variation for a single species, here likely driven by temperature differences and additional biotic and abiotic drivers across the elevational range. Improved understanding of the extent and implications of intraspecific variability is necessary for reliable quantifications and predictions of the impacts of environmental change, especially in understudied, hyper‐diverse ecosystems such as tropical forests.
Full-text available
Nerium oleander (Apocynaceae) which spread over a wide area along the Mediterranean coast, is an important indicator plant of Mediterranean elements. The objective of the current research was to reveal the altitude effect of N. oleander in the Middle-West Taurus region situated in Turkey. In this study, it is statistically evaluated that the micromorphological and anatomical changes observed in tissues of the leaves collected at different altitudes. Leaf structure of N. oleander demonstrated morphological, epidermal and anatomical alterations at various elevations. Statistical analysis was subjected to analysis of covariance (ANCOVA). According to the Levene test results, it is determined that the Wmed and Lmed averages of some anatomical parts such as spongy parenchyma cells, collenchyma and xylem layers, increase as the altitude escalates. This result has been supported by the correlative effect of locality and anatomical parts and it is significantly relating the measurement of Wmed (p = 0.000<0.05). In micro morphological studies, trichome density and cavities were seen in the stomatal crypt chamber, the sizes of the upper and lower epidermal cells and the structures of anticlinal walls were examined in the superficial incisions. Considering the altitudes starting from 3 m up to 898 m, it is observed that the trichomes on the leaf epidermal surface were observed to decrease as altitude increases, while any remarkable difference was not found for the trichomes located in the stomatal crypt. Notwithstanding, the crystals in the leaf mesophyll layer were more concentrated at low altitudes (3 m) while abundance decreased at higher altitudes (898 m).
Full-text available
Alternative methods were compared for determining the stomatal density of needles from two pine species. Densities estimated from air‐dried, whole needles using a binocular dissecting scope were compared to densities estimated from vacuum‐dried, intact needles using a scanning electron microscope and expanded peels (or macerated cuticles) using a compound light microscope. Differences among methods were expected from two sources: (1) expansion and shrinkage as a function of water content, and (2) differences in geometry of the measured surface. Estimates from the dissecting scope were similar to those from scanning electron microscopy ( t =0.509, n =21, P =0.62), presumably because both used dried, but otherwise intact whole needles. Light microscopy estimates, however, were lower than dissecting scope estimates ( t =−2.307, n =13, P =0.04). After adjusting for expansion due to hydration and changes in needle geometry, differences disappeared ( t =−1.205, n =13, P =0.25). These results are an important consideration for researchers reconstructing palaeo‐atmospheric conditions and assessing plant response to environmental change.
Development of the resin duct cavity, sites of resin synthesis in the epithelial cells and elimination of resin from the protoplast were studied in roots of young Pinus halepensis seedlings. It is suggested that the Golgi bodies are involved in dissolution of the middle lamella in the region of the future duct cavity by secretion of lytic enzymes into the cell walls. In early stages of duct development osmiophilic droplets were observed in plastids, periplastidal and cytoplasmic ER, Golgi vesicles, mitochondria, nuclear envelope and in the cytoplasm. In the latter they were often observed to be surrounded by a membrane. Electron micrographs suggested that elimination of resin droplets from the protoplast occurs by their becoming surrounded by plasmalemma invaginations.
The area above the treeline in the European mountain ranges varies from ca. 1% (Corsica) to about 14% in the Caucasus (Table 29.1). The biota in the alpine zone across the different mountain systems is rather heterogeneous, as illustrated by a comparison of their alpine floras (Chap. 5). Mountain ranges such as the Alps and the Pyrenees, which are similar, contrast with ranges that have very little in common with the others (e.g. Sierra Nevada, the mountains of Crete). This heterogeneity is also evident when comparing treeline tree species in the different mountain systems (Table 29.2). An assessment of the climate in the alpine zone, based on soil temperatures at 10 cm below ground, indicated a mean growing season length of 155 (min. 105, max. 190) days year-1 across Europe (Chap. 2). Seasons tended to be slightly warmer in the south, particularly with regard to thermal sums (Chap. 2). However, no systematic differences in growing season length were observed across Europe, and absolute minima (mean -5 °C; range 0–15 °C) or maxima (mean +17 °C; range 12–19 °C) did not show any significant latitudinal trend, but depended on local snow cover and exposure.
The hypothesis is tested that global increases of CO2-concentration reduce stomatal density. Historical and recent data for leaves of over 200 plant species are compared. Statistically significant differences in stomatal density occur neither in lowland, nor in alpine plants over the 7 to 12 decades spanning of this comparison.
This book is an illustrated comprehensive account of living and fossil gymnosperms in 24 chapters. Chapters 1 and 2 (Introduction; and Seed development) give a general account and describe similarities and dissimilarities with pteridophytes and angiosperms. Chapter 3 deals with classification. The next 19 chapters (4-21) deal sequentially with fossil and living taxa: Progymnospermopsida (4), Gymnospermopsida (5), Gymnospermopsida - Cycadophytes (6-8), Gymnospermopsida - gymnosperms of uncertain relationship (9-12), Gymnospermopsida - Coniferophytes (13-16), Gnetopsida (17), Ephedrales (18), Welwitschiales (19), and Gnetales (20). Phylogenetic relationships are considered for each order, but chapter 21 specifically discusses phylogenetic considerations in Ephedra, Welwitschia and Gnetum. Chapter 22 describes in vitro experimental studies on the growth, development and differentiation of vegetative organs and tissues. Chapter 23 discusses the economic importance of gymnosperms, and chapter 24 presents concluding remarks. Overall, there is complete coverage of significant findings concerning morphology, anatomy, reproduction, embryology, cytology (chromosome numbers), and evolutionary trends and phylogeny. Ultrastructural and histochemical details are given where considered necessary.
This chapter highlights the evolutionary and ecophysiological responses of mountain plants to the growing season environment. The responses of mountain plants to their environment are due to a complex mixture of genetic and environmental influences. Plants growing on mountains experience reduced temperatures and vapor pressures with altitude, as well as a reduction in the partial pressure of air. There are many morphological, physiological, and biochemical features of plants that change with altitude, such as decrease in stature. Model simulations of canopy energy balance and CO2 fixation indicate that canopy structure and leaf area index (LAI) strongly influence both photosynthetic rate (A) and the ratio of 13C to 12C (δ13C) in leaves. δ13C measurements on expanded leaves provide a time integral of CO2 discrimination during the photosynthetic life of the leaf; they also include some unknown δ13C contribution from photosynthate exported or remobilized from other leaves and organs. The model simulations, for just the period of peak irradiance during the day, indicate that the energy balance and gas exchange of a leaf are dependent on its aerodynamic coupling with other leaves in the plant canopy, and with the air at some reference height above the canopy.
The El Niño-Southern Oscillation event of 1982-83 was associated with severe winter weather in California, including increased snow accumulations in the Sierra Nevada relative to 1984. We examined the ratio of 1983 needle length to 1984 needle length in two speces of pines growing near timberline in the Sierra Nevada for evidence of growth depression during the El Niño year. Trees of both Pinus albicaulis (whitebark pine) and P. contorta var. murrayana (lodgepole pine) were sampled from four topographic positions at the study site: a meadow on the valley floor, north- and south-facing slopes, and at high elevation near treeline. In all cases, average needle length in 1983 was less than that in 1984. The degree of growth depression varied among topographic positions and between species. Whitebark pines displayed the greatest variation in sensitivity to climatic change. Differences in sensitivity between species were associated with habitat restrictions; e.g., whitebark pines at high elevations were least affected by the El Niño year, while lodgepole pines were most affected when growing at high elevations. It is hypothesized that observed variation in growth depression among topographic positions is due to both differences in the length of the 1983 growth season associated with timing of snowmelt and decreased temperatures during the 1983 growing season.