Pinus bungeana Zucc.ex Enal

Lacebark pine （Pinus bungeana）, an evergreen conifer species native to China, is noted for its graceful profile. It has a height up to 30 m. Bark on young trees smooth, dull grey, scaling off in small patches like a plane tree, changing to chalky-white on old trunks, by which the species can be recognized from a long distance.

Effects of priming treatments on germination and biochemical characteristics of Pinus bungeana seeds

This experiment was conducted to evaluate the effect of seed priming on the germination and physiology of Pinus bungeana seeds. Seeds were treated by hydropriming with distilled water, halopriming with potassium nitrate （KNO3） at -0.3, -0.6, -1.2 MPa respectively （untreated dry seeds were taken as control）. Properties of seed germination and physiology were determined and the effect of hydro- and halopriming on germination and physiology ofP. bungeana seeds were investigated. The results showed that, compared with control, each priming treatment had increased the germination percentage （GP） and germination index （GI）, shortened the mean germination time （MGT） and the time required for 50% of the seeds to germinate （Gs0）. Primed P. bungeana seeds significantly decreased the relative conductivity and the amount of malondialdehyde （MDA）. Of all the treatments applied to seeds of P. bungeana, halopriming at -0.3 MPa KNO3 produced the highest GP （65.0%） and the shortest MGT （l 8.8 d） and Gs0 （18.2 d）.

Allozyme Genetic Diversity and Conservation Strategy of Ten Natural Populations of Pinus bungeana Zuuc. ex Endl

Pinus bungeana is a three-needle pine with typical fragmented distribution in central and northwestern China. Its natural resources are gradually decreasing and need to be conserved. For conserving genetic diversity of P. bungeana, the authors sampled 10 natural populations in its distribution areas and conducted the analysis of isozymes. Thirty one loci with 53 alleles on the basis of 16 enzyme systems were assayed. The parameters of genetic diversity at species and population level are respectively as follows: As = 1.742, Ae[s] = 1.49, Ps = 54.8%, He[s] = 0.162, Ap = 1.39, Ae[p]= 1.30, Pp = 34.85, He[p] = 0.0986. In comparison with other pines, P. bungeana possesses a slightly low amount of genetic variation especially at the population level. By contrast, the level of population genetic differentiation (GST = 0.135) is higher compared to other pines. All ten populations are divided into three groups according to Nei抯 genetic identity (I). There is a slight relation (r = 0.31) between genetic distance and geographical distance. Some populations are obviously deviate from Hardy-Weinberg equilibrium but the total population is basically accordant with Hardy-Weinberg equilibrium. The correlation analysis between allele frequencies and ecological factors showed that the alleles at loci of Idh and Pgi-2 had gradient variation trends of their frequencies. The sample capturing curves?analysis indicated that the captured alleles increased when the number of sampled populations increased and 99% out of whole allele pool of ten populations would be captured when five populations were randomly selected. At last, the population genetic structure of P. bungeana and its conservation strategy were discussed.

Assessing frost hardiness of Pinus bungeana shoots and needles by electrical impedance spectroscopy with and without freezing tests

Aims Nursery and forest operations require that frost hardiness results be produced faster than can be provided by controlled freezing tests.There is a great challenge to develop a rapid method for predicting frost hardiness that might not necessitate controlled freezing tests.The aim of this study was to examine the assessment of the frost hardiness of shoots and needles of Pinus bungeana by electrical impedance spectroscopy(EIS)with and without controlled exposure to freezing.Methods The frost hardiness of current-year shoots and needles of P.bungeana in an 8-year-old provenance field trial was measured at Shisanlin Nursery in Beijing,China,from September 2006 to January 2007 by means of EIS and conventional electrolyte leakage(EL).In the same plants,but without controlled freezing test,were monitored the EIS parameters in current-year shoots and needles.Important Findings The results showed that(i)after controlled freezing tests,the frost hardiness estimated by EIS parameters(extracellular resistance,re,and membrane time constant,sm)was significantly correlated with the frost hardiness assessed by EL method(r=0.95)and(ii)for the samples not exposed to controlled freezing treatment,the relaxation time s1 for shoots and b for needles had greater correlations with the frost hardiness estimated by EL after controlled freezing tests relative to the other parameters(r=
0.90 for shoots and r=0.84 for needles,respectively).The parameters re of shoots and needles and sm of needles might be applied for measuring frost hardiness of samples after exposed to controlled freezing tests.The frost hardiness results can be obtained within 48 h.The parameters s1 of shoots and b of needles could be used for estimating the frost hardiness of samples without using a controlled freezing test.The frost hardiness results can be obtained within 24 h.