春季柑橘幼树生长对红壤水分条件的响应

以第四纪红黏土发育的红壤、2年生宫川温州蜜柑(Citrus unshiu Marc.cv.Miyaga Ma Mase)盆栽幼树为材料,采用土壤水分探头(FDR)实时监测红壤水分含量,控制红壤水分设5个处理:SMC30、SMC45、SMC60S、MC75和SMC90(分别代表红壤相对含水量的30%、45%、60%、75%和90%),研究了红壤水分条件对柑橘幼树根、叶、春梢和横径的影响。结果表明,当红壤水分为SMC75时最适合柑橘幼树生长,且柑橘幼树根、春梢和横径及叶面积、周长、宽生长参数均在此处理时达最大值。幼树根生长指标(根体积、总根长、根上下扫描面积和根表面积)均与红壤水分间呈极显著抛物线相关,叶形态指标(叶面积、叶周长、叶宽、叶长、叶长/宽比值、叶形状因子)以SMC75为界,随着红壤水分的增加或减少,其生长量均受到了一定程度的影响。SMC≤45%,幼树春梢长和横径受到显著抑制。

RESPONSE OF MOISTURE CONTENT OF RED SOIL ON GROWTH OF CITRUS(Citrus unshiu Marc.)SAPLINGS IN SPRING

In this study,2-year potted seedlings of satsuma mandarin(Citrus unshiu Marc.cv.MiyagaMa Mase) was selected as experimental material,and growing in red soil from Quaternary red clay to explore the effects of 5 soil moisture contents on growth of citrus saplings.The red soil moisture content was real time monitored by FDR and controlled exactly in five treatments of SMC30,SMC45,SMC60,SMC75 and SMC90(SMC means soil moisture content,five treatments were the 30%,45%,60%,75% and 90% of maximum water content in red soil field,respectively).The result showed that it was optimal for growth of citrus saplings when SMC was about 75%.With increasing of red soil moisture content,the root, spring shoot,cauline diameter,leaf area,leaf perimeter and leaf width all reached max valves when SMC was 75%.The index of roots growth,which included the root volume,total root length,root project area and surface area,had positive-significantly parabolic correlations with SMC.The index of leaves growth,including the leaf area,leaf perimeter,leaf width,leaf length,ratio of leaf length to width and leaf factor,were all affected to a certain extent whenever SMC was more or less by 75% as a boundary.Spring shoot length and stem diameter were inhibited when SMC was below 45%.