遮阴处理对粗肋草生长、光合特性和养分质量分数的影响

Effects of Shading on the Growth,Photosynthetic Characteristics and Nutrient Accumulation of Aglaonema commutatumd

为了解粗肋草需光特性及其对不同光强的响应特征,以盆栽粗肋草“如意”为材料,设置0(CK)、25%(T1)和50%(T2)3个遮阴处理,分析遮阴对“如意”生长、光合特性和养分元素积累的影响,为“如意”苗木优质高效栽培提供依据。结果表明:1)随着遮阴程度的增加,“如意”根和地上部生物量呈先升后降趋势,且在T1处理达到峰值,分别较CK增加90.91%和126.08%;2)除平均根直径外,随着遮阴程度的增加,根长、根表面积和根体积同样表现出先升后降趋势,并T1处理达到峰值,分别较CK提高66.25%、39.16%和65.58%;3)不同处理间,光合色素质量分数由大到小顺序为T2、T1、CK,且T2处理中光合色素质量分数均显著大于CK;4)与CK相比,遮阴处理提高了表观量子效率(Y_(AQ))、最大净光合速率(P_(nmax))和光饱和点,降低暗呼吸速率(R_(d))和光补偿点(P_(LC)),说明遮阴能提高P_(nmax)和Y_(AQ),并降低R_(d)和P_(LC),增强叶片对弱光的利用能力,促进碳同化产物积累;5)与CK相比,遮阴降低“如意”叶片中的初始荧光值(F_(o)),而提高最大荧光值(F_(m))、可变荧光值(F_(v))、PSⅡ潜在光化学效率(F_(v)/F_(o))、PSⅡ最大光化学效率(F_(v)/F_(m))、非光化学猝灭(Q_(NP))、光化学猝灭系数(q_(P))和PSⅡ实际光化学效率(Y_(Q));6)遮阴处理下植株地上部和根元素质量分数并无明显变化规律,但显著促进钾从根向地上部转运。综上所述,T1处理是适宜“如意”生长的光照条件,在该条件下“如意”通过促进光合色素质量分数,提高叶片PSⅡ反应中心的光化学效率和电子传递速率,同时提高叶片光合效率,进而促进植株的生长和根系发育。

In order to understand the light requirement of Aglaonema commutatum and its response characteristics to different light intensities.Pot seedlings of A.commutatum‘Red Valentine’were treated wit different shading treatments,namely,CK(0%),T1(25%),and T2(50%),the effects of shading on the growth,photosynthetic characteristics and nutrient accumulation were analyzed,providing theoretical basis for high quality and efficient cultivation of‘Red Valentine’seedlings.The results showed that:(1)With the increase of shading,the biomass of‘Red Valentine’roots and stems displayed first increasing then decreasing tendency,and reached its maximum at T1 treatment,which were 90.91%and 126.08%higher than CK,respectively.(2)A similar tendency to biomass of roots and shoots were also observed for roots length,roots surface area and roots volume,which were 66.25%,39.16%and 65.58%higher than CK,respectively.(3)Photosynthetic pigments content increased with the increase of shading,and arrived its maximum at T2,and the photosynthetic pigments content in T2 were significantly higher than that in CK(P>0.05).(4)Compared with CK,shading treatment increased apparent quantum efficiency(AQY),maximum net photosynthetic rate(P_(nmax))and light saturation point,while decreased dark respiration rate(R_(d))and light compensation point(LCP),indicating that shading could increase P_(n) max and AQY,and decrease R_(d)and LCP,enhanced the utilization capacity of weak light,thus promoted the accumulation of carbon assimilation products.(5)Moreover,shading treatment decreased the F_(o)value,while increased the values of F_(m),F_(v),F_(v)/F_(o),F_(v)/F_(m),NPQ,q_(P)and Q_(Y)in leaves of‘Red Valentine’.(6)No obvious changes of nutrients contents in roots and shoots of‘Red Valentine’were noted under shading treatment as compared with CK,but shading significantly promoted the translocation of potassium from roots to shoots.Taken together,T1 treatment is the most suitable light condition in our study for the growth of‘Red Valentine’,under such condition the growth of plant and the development of roots in‘Red Valentine’can be enhanced through increased the accumulation of photosynthetic pigments,which in turn improved the photochemical efficiency and electron transport rate of PSⅡ reaction center in its leaves,and improved the photosynthetic efficiency in its leaves as well.