越冬时葎草雌雄株生理反应和再生策略的差异分析

Differences in physiological responses and regeneration strategies of male and female Humulus scandens plants during wintering

以野生雌雄葎草为材料,通过测定越冬前(12月1日)、越冬中(1月15日)和越冬后(4月15日)雌雄株构件中可溶性糖(SS)、淀粉(ST)、丙酮酸(PA)含量和硝酸还原酶(NR)活性,测定越冬后构件存活率和再生率及再生构件性状与生物量分配比,分析雌雄株越冬时生理反应和再生策略的差异。结果表明:1)越冬前雄株叶片中ST含量小于雌株而SS含量大于雌株,其成熟茎和根的SS和ST含量均小于雌株(P<0.05),雄株通过提高叶中SS含量抵御寒冷,雌株通过转移糖分到茎和根应对寒冷;2)越冬前雄株叶和茎的PA含量显著大于雌株,根中含量显著小于雌株(P<0.05),构件中NR活性无性别差异(P>0.05),雄株通过增强茎和叶的呼吸抵御寒冷,雌株通过根储备营养应对寒冷;3)越冬后雌株再生叶的SS和ST含量大于雄株(P<0.05),PA含量和NR活性小于雄株,其再生代谢基础高于雄株;4)越冬时雄株植株存活率为26.67%,为雌株植株存活率的34.78%,雄株存活植株的茎存活率仅为雌株的32.24%,越冬后雌株茎、叶再生率仅为雄株的21.03%和23.82%,而花序再生率高达74.40%;5)雌株再生叶数和叶面积及再生茎长小于雄株(P<0.05),其再生茎和叶生物量分配比仅0.59%和1.31%,再生花序分配达98.09%,其再生花序柄和花序轴长及小花数大于越冬前正常花序,且萼片面积增大且生物量分配比占31.26%,总面积达624.92 cm^2·株^-1,为再生叶总面积的24.50倍。越冬时雄株通过生理反应抵御寒冷,使茎和根贮藏物质低于雌株,故其存活率和再生率低于雌株。越冬后雄株再生生物量仅1.57 g·株^-1全部分配到营养器官,雌株再生总生物量达32.05 g·株^-1,且98.09%分配到花序,萼片代替叶片为主要光合器官,为花序形成和开花就近提供养分。

This research studied the wild dioecious climbing herb Humulus scandens,in order to analyze the differences in physiological response and regeneration strategies between male and female plants,while over-wintering.Various physiological data,including soluble sugar(SS),starch(ST),and pyruvic acid(PA)contents and nitrate reductase(NR)activity of male and female plant parts(young leaves,mature leaves,mature stems,roots)were determined before winter(December 1),during over-wintering(January 15)and after winter(April 15).Survival rate and regeneration rate of plant parts biomass allocation ratio were also determined after wintering,to give insight into differential biomass allocation strategy of male and female plants.The results showed:1)The ST content in the leaves of male plants before wintering was lower than that in female plants,and the content of SS and ST in mature stems and roots were lower than those in female plants(P<0.05).Male plants resisted cold by increasing SS in leaves,while female plants responded to cold by transferring sugar to the stems and roots.2)The PA content of male plant leaves and stems was significantly higher than that in female plants before wintering,but PA content in male plant roots was significantly lower than that in female plants(P<0.05).There was no gender difference in NR activity of plant modules(P>0.05).Male plants resisted cold by enhancing the respiration of stems and leaves,while female plants responded to the cold through utilization of substrate reserves in the roots.3)The content of SS and ST in the regenerated leaves of female plants was higher than in male plants(P<0.05),and the PA content and NR activity in leaves were both lower than in male plants.The PA content increased over winter in the female mature stems yet decreased in male plants(P<0.05).The metabolic activity involved in female plant regeneration was higher than that of male plants.4)The survival rate of over-wintering male plants was 26.67%,while survival rate of female plants was 76.7%.The survival rate of stems in male plants was only 32.24%of that in female plants(12.50%and 38.77%,respectively).The regeneration rates of plant parts were,for male and female plants,respectively:leaves 5.85%and 1.23%,stems 13.10%and 3.12%,while inflorescence regeneration in female plants was 74.40%.5)The number of regenerated leaves,the leaf area,and the length of the regenerated stems of female plants were all lower than those of male plants(P<0.05).The total biomass proportion contributed by regenerated stems and leaves was only 0.59%and 1.31%,respectively,while the contribution to total biomass of regenerated inflorescences was 98.09%.The regenerated inflorescence stalk and axis length and floret number of regenerated inflorescences were larger than those of inflorescences observed before winter.Sepals exhibited increased area and greenness,and accounted for 31.26%of total biomass in regenerated plants,and their total area was as much as 625 cm^2·plant^-1,compared with a total area of regenerated leaves of 25.51 cm^2·plant^-1.During overwintering,male plants resisted cold through physiological response,in which the stored substrates of male stems and roots were lower than those of female plants.Thus the survival rate and regeneration rate of male plants were lower than those of female plants.After wintering,the biomass of regenerated male plants was only 1.57 g·plant^-1 and all of this was allocated to vegetative organs.By contrast,the average biomass of female plants was 32.05 g·plant^-1,and 98.09%of this was allocated to inflorescence formation with sepals instead of leaves being the main photosynthetic organs,providing nutrients for inflorescence formation and nearby flower development.