Effects of Different Treatments on Seed Germination of Zanthoxylum nitidum(Roxb.)Seed

[Objectives]This study was conducted to improve the germination rate of Zanthoxylum nitidum(Roxb.)seeds and shorten the germination period.[Methods]Different germination beds,seed soaking temperatures,seed soaking time and culture temperatures were set to study the effects on seed germination of Z.nitidum.[Results]The germination rate on the filter paper germination bed was stable and it was easy for the control of humidity.The germination rate of seeds soaked in warm water at 50℃for 24 h was about 53.33%.The germination rate of seeds cultured at 25℃was as high as 91.98%.[Conclusions]This study provides a theoretical basis for seedling breeding and large-scale production of Z.nitidum.

Application of oxygen-sensing technology to measure seed quality of Ginkgo biloba

Germination tests are currently the most widely used method to evaluate seed quality of Ginkgo biloba L., but they are time-consuming and labor intensive. Oxygen-sensing technology, based on the principle of fluorescence quenching to detect oxygen and assess seed quality was used to rapidly evaluate seed quality of two varieties (Shandong Tancheng 202 and Zhejiang Dafoshou) of G. biloba from five mother plants. Fifteen samples of three vigor levels were produced by accelerated aging treatments. This process was applied in duplicate. A portable oxygen-sensing detector was employed to measure oxygen content during seed germination in a closed system at 25 A degrees C each day until day 14. Four oxygen metabolism indices were calculated: oxygen consumption index, oxygen consumption rate, critical oxygen concentration, and theoretical germination time (T (GT)). Additionally, we tested laboratory germination and field emergence. The results of a one-way analysis of variance and correlation analysis showed that T (GT) was the candidate index to evaluate seed quality of G. biloba. Therefore, the T (GT) value was used to validate the reliability of oxygen-sensing evaluation for Zhejiang Dafoshou seeds kept under four storage conditions. The trend in the change in oxygen metabolism agreed completely agreement with that of seed germination under all storage conditions. The oxygen-sensing test reliably and rapidly assessed seed quality of G. biloba. The germination rate of Zhejiang Dafoshou was accurately predicted by T (GT).

Influence of smoke, heat and fire on germination of woody species occurring in the dry valleys of southwest China

Aims Savannahs depend on fire for their persistence.Fire influences regeneration from seeds in several ways:it converts the environment into a more open space which can benefit the establishment of seedlings,and fire itself can also enhance germination by chemical and physical cues,such as smoke and heat.There is limited information as to how seed of Asian savannah species respond to fire,even though Asia has several dry vegetation types that are associated with fire.Our main question was whether fire enhances or triggers the germination of woody species occurring in southwest Chinese dry valleys,which have savannah vegetation.Methods We conducted tests with heat(80°C)and smoke solution treatments,and tests with real fire by burning grass on top of sand trays containing seeds.We tested 35 species,including savannah species,and gully and forest species.Depending on seed availability,not all species were tested for all treatments.Twenty-six species had total germination>4%and these were used for analysis.Important Findings Heat increased germination of three species(strongest reaction:Dodonaea viscosa),smoke increased germination of five species(strongest reaction:Calotropis gigantea).Both treatments decreased germination for five and seven species,respectively.Real fire was detrimental for most species,except for D.viscosa,which is known to respond positively to heat shock.Even though fire-related cues were not a trigger for germination for most species in our study,fire could still be crucial for regeneration by competition release.

Geographical variation in germination traits of the salt-marsh cordgrass Spartina alterniflora in its invasive and native ranges

Aims Germination is the earliest life-history transition of a plant species.It determines the ecological breadth and geographic ranges of a species and has major effects on its invasion potential.The largest spread of the invasive salt-marsh cordgrass Spartina alterniflora in China,where it extends to latitudes lower than its native range in North America,provides an opportunity to examine germination trait variation across latitudes within and among its invasive and native ranges.Methods We studied seed germination traits of S.alterniflora using seeds collected from 10 locations across latitudes in its invasive range(China,20°–40°N)and 16 locations across latitudes in its native range(USA,27°–43°N)in growth chambers with 0 PSU sterilized distilled water.We further evaluated how climate and tide range in the original locations influenced germination traits.Important Findings Native populations showed higher(~10%)germination percentage and significantly higher(~20%)germination index than invasive populations did,but invasive populations germinated significantly earlier(~3 days)than native populations.Germination percentage and germination index increased with latitude in the invasive range but decreased with latitude in the native range.The mean germination time decreased with latitude in the invasive range and paralleled that in the native range.Germination percentage and germination index were negatively correlated with mean daily temperature(Tmean),mean daily maximum temperature(Tmax)and mean daily minimum temperature(Tmin),and inversely correlated with Tmean,Tmax and Tmin in the native range.However,the mean germination time was positively correlated with Tmean,Tmax and Tmean in both ranges.Our results demonstrate that invasive and native populations have evolved different latitudinal clines in germination percentage and index,but the mean germination time of the invasive population mirrored the latitudinal cline observed in the native range,suggesting that germination strategy across latitudes may change during invasion process.

comLocal adaptation to distinct elevational cores contributes to current elevational divergence of two Aquilegia vulgaris subspecies

Aims Phenotypic plasticity and local adaptation of populations at their distributional limits are crucial to understand species colonization and persistence in novel or marginal environments,as well as spe-cies divergence and niche width evolution.We assess the contri-bution of these processes to shape current elevational limits and determine elevational phenotypic divergence between two subspe-cies of Aquilegia vulgaris(subsp.vulgaris and nevadensis).Methods We conducted sowing and transplant experiments considering four elevations throughout the current elevational range of A.vulgaris in southern Iberian Peninsula.Experiments were designed to explore,on the one hand,local adaptation through three components of performance(germination,survival and growth)and,on the other hand,the phenotypic differentiation and/or plasticity associated to local adaptation.Four populations per subspecies(three from the elevational core and one from the elevational boundary)were used as seed sources.Patterns of local adaptation and phenotypic differentiation are examined in the context of the‘centre-periphery’hypothesis.Important Findings Central populations of both subspecies performed better at their local elevations while marginal populations were maladapted,confirming the hypothesis and contributing to explain the current elevational segregation of these subspecies.Density of glandular pubescence and germination timing seem to be related to local adaptation,through phenotypic differentiation between subspe-cies or elevations.The widespread subsp.vulgaris showed signals of adaptive plasticity in the timing of germination while it was not the case in the endemic subsp.nevadensis.