贵州30个竹种枝叶化学计量和生物量分配特征

Stoichiometric characteristics on branches and leaves of 30 introduced bamboo species of Guizhou

竹子具有较强的表型可塑性,母竹与其繁育出的新竹具有不同的生长策略。研究春、夏季新竹和母竹枝叶生态化学计量特征和生物量分配模式,对竹种栽培具有一定的指导意义。分别于春季(4月)和夏季(8月)对百里杜鹃竹博园内30个竹种新竹和母竹的近2年生枝叶C、N、P、K含量及化学计量比、枝叶生物量和含水率进行研究。结果表明:在春季,相较于母竹,新竹叶片中N、K和N∶P含量显著增加,C∶N降低;新竹枝N、P、K含量显著增加,C、C∶N显著下降。夏季时期,相较于母竹,新竹叶片C∶P、N∶P显著增加,P含量显著下降;新竹枝C∶N、C∶P增加,N、P含量降低。母竹叶片中C与P呈负相关,C与C∶P和N∶P呈显著正相关,而新竹叶片C与其他元素无相关性;新竹枝、叶和母竹枝的N与P、K,P与K,C∶N与C∶P、N∶P,C∶P与N∶P呈不同程度正相关,N、P、K均与C∶N、C∶P和N∶P呈不同程度负相关。夏季新竹和母竹的枝、叶生物量均高于春季,夏季新竹枝叶生物量比率、枝叶含水率和母竹枝含水率显著高于春季,夏季母竹叶含水率显著小于春季含水率;在春季时,相较于母竹,新竹枝生物量、枝和叶含水率显著增加,叶生物量降低;而在夏季,叶生物量、枝叶生物量比显著降低。春季新竹生长期N、P、K主要用于枝叶生长而非固C,3种元素间存在协同关系,所以春季需满足新竹生长所需氮肥、磷肥和钾肥;夏季新竹会降低对N、P的吸收来提高C积累,夏季应减少N、P施加。新、母竹有不同的生物量分配策略:相较于母竹,新竹分配更多生物量给枝,更少的生物量到叶片,新竹枝叶含水率显著高于母竹。

Great variation is often found in the bamboo with the high phenotypic plasticity under different growth strategies,particularly for the mother bamboo and its new bamboo.This study aims to analyze the ecological stoichiometric characteristics for the biomass distribution of the branches and leaves.A systematic investigation was also implemented to explore the C,N,P,and K content and their stoichiometric ratio,leaf biomass and moisture content of 30 bamboo species in the Hsinchua bamboo and mother bamboo in spring(April)and summer(August).The results show that the contents of N,K and N∶P in the Hsinchu leaves increased significantly in spring,whereas the C∶N ratio decreased,compared with the mother bamboo.The contents of N,P and K in the Hsinchu branches increased significantly,whereas,the contents of C and C∶N decreased as well.By contrast,the leaves of Hsinchu increased by C∶P and N∶P,whereas,the P content decreased significantly in summer,compared with the mother bamboo.Furthermore,the C∶N,and C∶P of Hsinchu branches increased,whereas,the content of N and P decreased.Moreover,the contents of C and P were negatively correlated with the leaves of mother bamboo,whereas,the C content was positively correlated with C∶P and N∶P.But there was no correlation between the C and other elements in the Hsinchu leaves.The N content of Hsinchu branches,leaves and mother bamboo branches were positively correlated with the P,K,P and K,C∶N and C∶P,N∶P,C∶P and N∶P,while,the N,P and K contents were negatively correlated with the C∶N,C∶P and N∶P.The branch and leaf biomass of Hsinchu and mother bamboo in summer were higher than those in spring.There was an increasing variation in the branch and leaf biomass ratio and moisture content,as well as the branch moisture content of Hsinchu in summer,compared with the spring.Nevertheless,the moisture content of summer mother bamboo leaves was significantly smaller than that in spring.Meanwhile,Hsinchu branch biomass,branch and leaf moisture content increased significantly in spring,whereas,the leaf biomass and its ratio decreased,compared with the mother bamboo.The N,P and K of Hsinchu were used mainly for the branch and leaf growth rather than solid C in spring.There was a synergistic relationship between the N,P and K elements.As such,the N,P and K fertilizers were required for the Hsinchu growth during this time.The Hsinchu was reduced the absorption of N and P for the increase of C accumulation.The application of N and P should be reduced in summer.Different strategies of biomass allocation were achieved for the new and mother bamboo:the Hsinchu can be allocated more biomass to the branches but less biomass to leaves,compared with the mother bamboo.There was the relatively higher moisture content of Hsinchu branches and leaves.The finding can also provide the strong reference for the bamboo cultivation.