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Seed germination trends of endemic vascular plants in the

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					Seed germination trends of endemic vascular plants in the Valencian
Community (Spain).


M. C. ESCRIBÁ1, E. LAGUNA1 & M. GUARA2

1 Generalitat Valenciana, Conselleria de Medi Ambient, Servei de Conservació i Gestió de la

Biodiversitat, C/. Arquitecto Alfaro, 39, E-46010 València, Spain (E-mail: floraval@gva.es).
2 Departament de Botànica, Universitat de València, Facultat de Ciències Biològiques, Av. Dr.

Moliner, 50, E-46100 Burjassot, València, Spain (E-mail: Miguel.Guara@uv.es).


Summary


Seed germination is a critical phase in the reproductive cycle of great importance for species
fitness, and variation in germination percentage has been interpreted as an adaptation to
ecological conditions. Understanding the germination process will help in the conservation
strategies, especially ex situ strategies in order to obtain seedlings in greehouse.

Germination test were carried out with seeds of 56 endemic, rare or threatened plants species
collected between 1996 and 2002 in different populations localities from the Valencian
Community.

Correspondence analysis (CA) on the germination percentage matrix displays a gradient
ordination onto axes I-II (43.37%). Cluster analysis on the three first axes point out three day-period
germination groups, and four species groups. Trends of two Silene hifacensis populations
considered in these analyses are different.


Introduction

Seed germination is a critical phase in the reproductive cycle of great importance for species
fitness, and variation in germination percentage has been interpreted as an adaptation to
ecological conditions (NAVARRO & GUITIÁN, 2003). Understanding the germination process will
help in the conservation strategies, especially ex situ strategies in order to obtain seedlings in
greehouse.

The aim of the present communication is to show the germination capacity of the different
endemic vascular plants, not previously studied, collected in the Valencian Community and, to
analyze possible similarities among species and populations.


Methods

Germination test were carried out with seeds of 56 endemic, rare or threatened plants species
collected between 1996 and 2002 in different localities from Valencian Community and
bordering territories. Only, there were sampled two populations of Silene hifacensis (Figure 1).
Seeds collected were cleanned and dryed progressevely up beetwen 30 and 45 days, then
preserved in cold storage at 4º C. Previous shown, seeds were summerged during 10 minutes in
NaClO. Incubated in a SANYO MLR-350 chamber at 18ºC-20ºC and 10ºC with 8 hours periods and
total period of light of 10 hours, during 30 days calculating the germination percentage daily.
Water was until the saturation point.

With the percentage data of diary germination, a Correspondence Analysis (CA) was carried out
to detect tendencies among species. A Cluster Analysis (Single, Complete and UPGMA methods)
based on euclidean distance with the species-points and day-points coordenates of the three
first factorial axes (FOUCART, 1982) to detect species-groups and days-groups was executed. The
best dendrograms were selected for interpretation after Mantel test. Multivariate statistics
package NTSYS-pc 2.1 (ROHLF, 2002) was used for ordination and cluster analysis.
Results

Germination test

After the incubation period, only seeds of two species, Iberis carnosa subsp. hegelmaieri and
Hippocrepis valentina, germinated completely and a few species passed the 95% (Centaurea
saxícola, Saxifraga longifolia, Dianthus multiaffinis, Dipcadi serotinum, Aster aragonensis, Biscutella
montana, Armeria alliacea subsp. alliacea). Between the 70% and the 95% of germination there
are 19 species (Diplotaxis ibicensis, S. hifacensis –population 1–, Jasione mansanetiana,
Vaccinium myrtillus, Gypsophila tomentosa, Seseli montanum subsp. granatense, G. struthium, S.
diclinis, Sideritis spinosa subsp. subespinosa, Lycium intricatum, Teucrium lepicephalum, T. flavum,
Senecio auricula, D. turolensis, Erodium aguilellae, Thymus willkomii, Vella lucentina, Muscari
neglectum, Petrocoptis pardoi). S. hifacensis –population 2– reached the 63.5% of germination at
the end. Twenty-eight species has passed the 70% at the end of 30 days period.

Thirtytwo species reached or passed the 50% of seed germination at 15th day (those previously
denoted, excepting E. aguilellae and T. flavum, and Biscutella lucentina, Dianthus hispanicus
subsp. edetanus, Echium saetabense, Helianthemum caput-felis, Muscari atlanticum, Sideritis
javalambrensis, Thymus granatensis subsp. micranthus, Verbascum fontqueri). And the same
percentage at 5th day by only 11 species (A. alliacea subsp. alliacea, A. aragonensis, B.
montana, D. multiaffinis, D. turolensis, D. ibicensis, G. tomentosa, G. struthium, I. carnosa subsp.
hegelmaieri, S. diclinis, V. lucentina).



               Accumulated percentage of germination


  100

   90

   80

   70

   60

   50

   40

   30

   20

   10

   0
        1      2      3   4      5     6   7     8   9   10     11   12   13       14   15    16       17   18     19      20   21     22     23   24   25   26   27     28   29   30
            A_alli            A_font       Ast           B_mon            B_luc              M_atl               M_neg               Dipc           C_sax         C_lag        Days
            D_mul             D_tur        D_edet        Dipl             Conv               Chei                Card                Lina           E_sang        E_agui
            Eryn              Gera         G_tom         G_stru           H_cap              H_squ               Iber                Jasi           Leuc          Lyci
            Echi              Hipp         Onon          Peri             Petr               R_str               R_bar               Saxi           Sene          Sese
            S_gla             S_spin       S_ede         S_jav            Si_vir             Si_hif1             Si_hif2             Si_dic         T_flav        T_lep
            T_wilk            Th_mic       T_pul         Vacc             V_luc              V_sp                V_font



                     Figure 1. Accumulate percentage of seed germination of species considered.


Comparison among species and germination days

Ordination

Correspondence analysis (CA) on the germination percentage matrix displays a gradient
ordination onto axes I-II (43.37%) –arch effect– (Figure 2). The first eight germination days are
located against the rest of days by the factorial axe I (28.61%), ordering species as a function of
germination start time. Those were earlier germination with a pick over the 4th or 5th day (Armeria
alliacea subsp. alliacea, Aster aragonensis, Biscutella montana, Dianthus multiaffinis, Diplotaxis
ibicensis, Gypsophila struthium, G. tomentosa, Silene diclinis, Thymus granatensis subsp.
micranthus, and Vella spinosa), were located at the right side. In front of these species, those with
later germination with a pick over the 14th-15th or 19th days (Saxifraga longifolia, and Senecio
auricula) were located at the left side.
The factorial axe II (14.76%) located in the right extrem the first four days, in the middle the 5th to
13th germination days, and the last seventeen days in the left extrem. Species were ordered
species with a very earlier germination pick, 2nd or 3th day, (Convolvulus valentinus, Dianthus
turolensis and Helianthemum squamatum) against to species with middle later germination pick
,7th day, (Petrocoptis pardoi, Seseli montanum subsp. granatense, Thymus willkomii, and
Vaccinium myrtillus). The factorial axe III (11.24%) –not represented– arranges the 12th to 13th
germination days opposite to 30th day, ordering species with later germination pick (Centaurea
lagascae, C. saxícola, Eryngium ilicifolium and Muscari atlanticum) front to species with
germination delay and/or very later germination picks.




         2.04
                                                                                                                               H squ
                 d30


                                                                                                                                   d2
                                                                                                                 d1                       D tur
                                                                                                       Conv
         1.31          d28           d26d27
                        d29 Chei                                                                                        V luc
                           M neg
                               d25
                                              Peri                                                                            d3

                               T flav d23
         0.59                    d19Gera
                                      Lina
    II                                                                                                          Iber
                                                                           Onon
                                                  d21
                                                  S gla                                                                  V sp
                                                                                                                         Th mic
                                           d24d18 d16
                                      R bar d17                                                                        DiplB mon
                                              d14 Leuc                                                                 d4
                                             d15 d20               R str
                                                                                                           Ast
                                                                                                                        G
                                                                                                                       A Gtom
                                                                                                                         alli
                                                                                                                            stru
                                           d22 Sene Saxi
                                            Si hif2
                                             Card                                         Jasi                           D mul
                                               E agui                                                      H cap
         -0.13                                   d13 E sang                                                     d5
                                        Eryn atl V font
                                              M         C lag                                                        Si dic
                                          C sax                         Lyci           D edet
                                                       d12d11                                         A font
                                                                Si vir    d10 d9 Dipc T wilk            d6
                                                                                          S spin
                                                                                         Echi B luc
                                                                     S ede        Vacc d8            S jav
                                                                    T pul                 Sese
                                                                                    Petr     d7         Hipp
                                                                          Si hif1
         -0.86
                                                                                                    T lep
              -1.72                       -0.97                            -0.23                    0.52                                1.27
                                                                    I (28.61%)


                      Figure 2. Correspondence analysis ordination on factorial axes I-II (43.37%).


Clustering

Cluster analysis on the three first axes point out three day-period germination groups (Figure 3).
The earliest germination days (group T1: first three days), the middle germination days (group T2),
with two subgroups (T2a: 4th to 10th days) and (T2b: 11th to 24th days), and the last germination days
(group T3: 25th to 30th days). These three day-period germination are consistent with the CA axes
interpretation below.

Respect to species, cluster analysis shows four species groups (Figure 4). The first group (S1), with
two subgroups, corresponding with earlier germination species with a pick over the 4th or 5th day
and middle earlier germination species with a pick over the7th or 8th day. The second group (S2)
formed by middle germination species with a pick on 12th to 14th days. The third group (S3) has a
primary very low germination pick over the 14th or 15th days and secundary pick few days later
(Muscari neglectum, Cheirolophus lagunae, Periploca laevigata subsp. angustifolia, Linaria
cavanillesii, Geranium sanguineum, Teucrium flavum, Sideritis glauca). Finally, the fourth group
(S4) has the earliest germination pick, 2nd or 3th day. As in the day-period germination groups,
these species groups are consistent with the CA axes interpretation below.
Discussion

There are two populations of a unique species, Silene hifacensis, not coincident in ordination
space or clustering. The population Si_hif1 has been included in group S1, while population Si_hif2
was in group S2. This circunstance seems more obvious among very different species
taxonomically separated, and not so clear in close species (same genus, e.g. Dianthus, Muscari,
Sideritis), but in multivariate analysis have not been considered other variables (habitat,
phenology, plant age, climatic conditions, etc.). As it has been suggested (see references in
Navarro & Guitián, op. cit.), variability in responses of seeds of different populations may be due
to environment differences ultimately responsible for corresponding genotypic differences.

Not all species have fully germinated during the tests, but a few germinated in a good
percentage. This aspect is very important if there is necesity of obtaining seedlings, but the test
was as simple as possible, based on International Seed Testing Association (ISTA) rules. Probably,
comparing separated populations, differences would be detected, and testing different
treatement conditions some germination percentage results were improved.


References

FOUCART, T.- 1982 - Analyse factorielle. Programmation sur micro-ordinateurs - Méthode +
      Programmes. Masson, Paris.

LAGUNA, E.; M.B. CRESPO, G. MATEO, S. LÓPEZ-UDIAS, C. FABREGAT, LL. SERRA, J.J. HERRERO-
      BORGOÑÓN, J.L. CARRETERO, A. AGUILELLA & R. FIGUEROLA - 1998 - Flora endémica, rara
      o amenazada de la Comunidad Valenciana - Generalitat Valenciana, Conselleria de
      Medi Ambient. Valencia.

NAVARRO, L. & J. GUITIÁN - 2003 - Seed germination and seedling survival of two threatened
      endemic species of the northwest Iberian Peninsula - Biological Conservation, 109: 313-
      320.

ROHLF, FJ. - 2002 - Ntsys. Numerical Taxonomy and Multivariate Analysis System. v. 2.1 - Exeter
       Sofware, Setauket, NY.

				
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