| One-year-old seedlings of Feng-yang No.1of Camellia oleifera seedlings werechosen as experimental materials, which were grown different water content ofsubstrates by weighting method, and the difference of physiological and biochemicalcharacteristics of C. oleifera seedlings were determined and analyzed. Six waterlevels respectively were100%–91%,90%–81%,80%–71%,70%–61%,60%–51%and50%–41%（T1, T2, T3, T4, T5and T6） of the seedlings weight （seedlings+substrate+substrate bags） when substrate water was saturation. To comprehend theadaptability and investigate response of physiology pattern of Camellia oleifera towater stress, the growth, the response mechanism of leaf anatomy structure andphotosynthetic characteristic was studied, to provide theoretical reference ofwater-control in C. oleifera production. The results are as follows:1. When the substrate water content less than80%W, the seedlings began todie.The number of death seedlings increased when the substrate water content lessthan60%W. Survival rate of T6just was4.7%.The shoots of T2growth were largerand the new shoots were5.21cm, new leaf number was4.89, leaf size were4.23cmand2.43cm. Biomass of fresh weigh was7.92g（dry weigh was3.44g）. Root/shootratio was smallest （fresh weigh ratio was0.4, dry weigh ratio was0.47）.2. The stomatic density, stomatic area per unit, size and aperture changed as thesubstrate water content decreasing. The stomatic density and area per unit of T2werelarge, but the stomatic size and aperture were small.The thickness, palisadeparenchyma, spongy parenchyma and the ratio of palisade to spongy of leaf declinedwith the decreasing of substrate water.3.The free water content, sum of free and bound water content, the ratio of freewater and bound water were decreased with the decreasing of substrate water content.But the content of bound water was increased. The free water content, sum of free andbound water content, the ratio of free water and bound water were largest （65.26%,67.74%and18.79%）.4. The relative conductivity and resistance showed different trend. Relativeconductivity was decreased and then increase （T2was smallest）.Resistance ofsurveyed parts of T1were largest, and new leaves were larger than the two-year-old 5. POD play a significant role when seedlings suffer from water stress as aprotective enzyme. The POD activity of T2was lowest.But the POD activity wasincreased when substrate water content lower or higher than this range.6. MDA content show a negative aparabolic curve with the substrate watercontent decreased. MDA content was decreased and then increased（T2was smallest）.Free proline and soluble sugar content rose with substrate water declining, whichvaried from231.4μm/g and681.4μm/g of T1to40.4mg/g and48.9mg/g of T5respectively.7. The chlorophyll and carotenoid content of T2respectively was the largest,with the value of1.000mg/g and0.140mg/g. The net photosynthetic rate,intercellular CO2density, transpiration rate, stomatal conductance and light useefficiency decreased with the decreasing of substrate water. The net photosyntheticrate of T2was largest (7.908μmol·m-2·s-1). Water use efficiency decreased first thenincreased with the decreasing of substrate water. The water use efficiency of T2andT5respectively were the lowest (2.186mmol·mol-1) and the largest (5.305mmol·mol-1).8. The seedlings of T2were optimal. While substrate water content dropped toless than81%W, the seedlings suffered drought stress. The seedling has strongadaptability, because it could adjust the leaf structure and photosyntheticphysiological characteristics according to the water stress in order to maintain thesurvival and growth. The substrate water content should be controlled in （90%W-81%W） to keep seedlings growing normally in C. oleifera production. |
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