| Camellia rubituberculata Chang ex Lin et Lu is endemic to Guizhou,with a narrow geographical distribution.The red flower and tumour-like protuberances on the fruit surface are special evolutionary developments in the Camellia genus,which have both scientific research and economic values.It is only found in the mountainous areas adjacent to Zima Township and Baling Town,Qinglong County,Guizhou Province,China.The population is scattered,the number of plants are scarce,the habitat heterogeneity is prominent,and the species is endangered.To strengthen the effective protection and rational utilization of C.rubituberculata,an experimental study was carried out to examine its biological characteristics,seed storage characteristics,seed germination characteristics,and population characteristics.The seed characteristics,population distribution characteristics,population spatial patterns,and population dynamics of C.rubituberculata were revealed.This paper discusses the factors endangering C.rubituberculata and protection strategies,and provides a reference for the protection and utilization of C.rubituberculata,as well as scientific research on the rare and endangered plants in Guizhou.The results were as follows:（1）The seed weight of C.rubituberculata was 1,466.60 g,which was a large seed.The seed viability,seed moisture content,pest rate,seed yield and water absorption of seeds were 96.00%,29.51%,12.50%,69.41%,and13.48%,respectively.The content of soluble sugar,fat,soluble protein,and starch were 23.91%,8.85%,16.69mg/g,and 15.51%.（2）The seeds of C.rubituberculata were intolerant to storage.When storing the seeds using sand cold storage,the effective storage time was 120 d.The content of soluble protein in the seeds initially increased,then decreased,and then increased.The content of fat and starch gradually decreased and that of soluble sugar gradually increased.After 120 d of storage,the germination rate of the seeds decreased sharply.The germination rate of seeds stored at room temperature was 8.00%;the germination rate of dried and refrigerated seeds was 4.00%;the germination rate of seeds refrigerated with mixed sand was the highest at 20.00%,while the seeds stored in freeze storage with dried and mixed sand did not germinate.（3）C.rubituberculata seeds germinated between 15～35°C.As the temperature increased,the germination rate and germination potential of the seeds increased and then decreased.The highest germination rate and potential,reaching 72.00%and40.33%,respectively,was at 20°C.When the temperature in constant,light did not affect the germination of the seeds.A gibberellin solution of 200 mg L-1could not promote the early germination of C.rubituberculata seeds but significantly increased their germination rate and germination potential.Different concentrations of potassium permanganate and polyethylene glycol solution did not promote the germination of the seeds.（4）Under the temperature conditions of 15,25,and 35°C,the soluble protein of C.rubituberculata seeds increased at the beginning of seed germination,then gradually decreased,while the rate of soluble protein decrease was fastest at 25°C.The content of soluble sugar initially decreased and subsequently increased.The content of crude fat did not change at the beginning of germination and subsequently decreased gradually.Malondialdehyde（MDA）content showed a positive increase with increasing temperature and reached a maximum at 35°C.Peroxidase（POD）,superoxide dismutase（SOD）,catalase（CAT）are mainly regulated by temperature.When the temperature was fixed,the different light times did not affect changes in the soluble protein,soluble sugar,crude fat,MDA,and antioxidant enzyme activity during the germination of C.rubituberculata seeds,which can be classified as light neutral seeds.（5）It was found that the original population structure of C.rubituberculata can be defined as a growth type,with abundant seedlings,and the population can be naturally renewed and will steadily increase.The spatial distribution of C.rubituberculata population of Carthamus sinensis mainly shows cluster distribution on small scale and random distribution on large scale.The population distribution pattern of the three developmental stages of young age,middle age and old age showed some difference.The spatial correlations of the different developmental stages mainly manifested as follows:the young trees and middle-aged trees in sample plot no.1 were negatively correlated with each other at all scales,the young trees and old trees were negatively correlated at the medium and small scales,and there were no correlations at the large scale.The middle-aged trees and the old trees did not correlate at any scale.In sample plot no.2,there was a negative correlation between young trees and middle-aged trees at the small scale and no correlation at medium and large scales;young trees and old trees were negatively correlated at the medium and small scales,but not at the large scale.There was no correlation between middle-aged trees and old trees at any scales.The young trees and middle-aged trees in sample plot no.3 were positively correlated at all scales;there was a negative correlation between young trees and old trees at the small scale but no correlation at the medium scale,and there was a positive correlation at the large scale;the middle-aged trees and old trees were not correlated at any scale.At the same time,the analysis of the dynamic quantification index of the population of C.rubituberculata showed that the overall change in the individual contribution potential had a wave-like fluctuation of"drop-up-down",and the population Vx was negative at the age of IV,indicating that the population was ecologically fragile and vulnerable to external environmental interference.The biological characteristics,habitat heterogeneity and vulnerability to disturbance,and limitation of the species to gullies in the distribution area are the main factors leading to population expansion and species dispersal. |
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