膜下滴灌和淹灌两种栽培模式下水稻光合生理特性的研究

以粳稻品系T-04和T-43为试材,通过盆栽控水试验,比较了在膜下滴灌和淹灌两种栽培模式下乳熟期叶片的光合色素含量、光合特性、叶绿素荧光参数和渗透调节物质含量的差异,分析了两种栽培模式下的水分利用效率和产量构成因素。结果表明,在膜下滴灌栽培模式下,2个水稻品系的水分利用效率显著高于淹灌,叶绿素a、叶绿素b、类胡萝卜素含量均降低;最大净光合速率、胞间CO2浓度、气孔导度、蒸腾速率显著降低,表明光合速率下降受叶绿素含量和气孔的双重影响;表观量子效率、羧化效率、ΦPSII、电子传递速率、Fv/Fm均显著降低,说明光合色素含量降低导致PSⅡ反应中心捕光能力减弱和光化学转化效率降低,从而使叶片光合速率降低;可溶性糖、可溶性蛋白均显著低于淹灌栽培;丙二醛、脯氨酸含量高于淹灌栽培,说明滴灌栽培水稻植株的膜脂过氧化加剧,细胞膜系统受到一定程度的破坏,通过主动积累渗透调节物质,适应干旱胁迫。膜下滴灌栽培水稻单位面积有效穗数和结实率显著降低,导致最终减产。

Photosynthetic Characteristics of Rice Under Drip Irrigation with Plastic Film Mulching and Continuous Flooding

Photosynthetic pigments contents,photosynthetic characteristics,chlorophyll fluorescence parameters, osmolytes,and water use efficiency(WUE) and yield factors at milky stage of two rice lines T 04 and T 43(Oryza sativa subsp. keng) were analyzed under traditional continuous flooding and drip irrigation with plastic film mulching in a pot experiment. The results showed that the WUE of rice   under drip irrigation with plastic film mulching were higher than that under traditional flooding, but chlorophyll a,chlorophyll b and carotenoids contents were significantly reduced compared with those under traditional continuous flooding.The maximum leaf net photosynthetic rate,relatively high intercellular CO2 concentration(Ci) and an equivalent stomatal conductance(GS),transpiration rate(Tr) were significantly lower than those under continuous flooding, indicating that the reduced photosynthetic rate was attributed to both chlorophyll contents and stoma.Apparent quantum efficiency(AQY), carboxylation efficiency(CE), ΦPSⅡ,electron transport rate (ETR) and Fv/Fm decreased significantly (P<0.05). Lower photosynthetic pigments contents might be the main factor to  low leaf photosynthetic rate which directly leads to 1ower light harvesting capacity and photochemical conversion efficiencies of the PSⅡ reaction center. The contents of soluble sugars(SS) and soluble proteins(SP) were lower, but both proline (Pro) and  malondialdehyde(MDA) contents were higher than those under continuous flooding cultivation,implicating  that  drip irrigation  with plastic  film mulching resulted in membrane lipid peroxidation,and cell membrane damage to some degree,  but activated osmolytes accumulation  thus  enhanced its drought tolerance. Effective panicle number per unit area and seed setting rate under drip irrigation with plastic film  mulching were significantly reduced,leading to a declined seed production.