红光与远红光比值对温室切花菊形态指标、叶面积及干物质分配的影响

以切花菊品种‘神马’(Chrysanthemum morifolium Ramat ‘Jinba’)为试材,于2010-2011年设计不同红光(R: (660 ±10) nm)与远红光(FR: (730±10)nm)比值(R/FR分别为0.5、2.5、4.5、6.5)的LED灯照射处理,研究不同R/FR值对温室切花菊形态指标、叶面积形成及干物质分配的影响。结果显示R/FR=2.5处理的植株叶片数、株高、茎粗、花径、叶面积及总干重均为各个处理中最高,R/FR=0.5处理的节间最长。所有R/FR处理的单株地上干物质重量与光质处理天数呈指数-线性模型。随处理天数的增加不同R/FR值处理菊花植株地上部分及地下部分干物质分配指数差异均不显著,叶片和花的干物质分配指数随处理天数的增加分别呈降低和升高的趋势,茎干物质分配指数则呈现先升高后降低的趋势,R/FR=2.5处理下,菊花叶片干物质分配指数和花干物质分配指数最高,而茎干物质分配指数却为最低;R/FR=6.5处理茎干物质分配指数最高,叶片干物质分配指数最低;0.5处理花朵干物质分配指数最低,说明远红光比例增加能够促进干物质向茎中分配,R/FR=2.5处理利于干物质向花朵中分配。

Effects of red/far red ratio on morphological index,leaf area and dry matter partitioning of cut chrysanthemum flower

Chrysanthemum is one of the four most important cut flowers in the world and is also China′s main export flower.To study the effects of the red to far red ratio of light on the morphological index,leaf area,and dry matter partitioning of chrysanthemum,experiments were conducted in the experimental greenhouse of Nanjing University of Information Science and Technology from October 2010 to February 2011.The greenhouse was 9.6 m wide and 30.0 m long,with top and shoulder heights of 5.0 m and 4.5 m,respectively.The experimental material was Chrysanthemum morifolium Ramat.cv.’Jingba’).The plants were transplanted on 6 October,when the seedlings were approximately 20 cm high with 6—10 leaves.A mixture of vermiculite and perlite with a volume ratio of 2∶1 was used as the culture substrate.The planting space was 20 cm × 20 cm in size.During the vegetative growth phase,fluorescent lamps(photosynthetically active radiation(PAR) =200 μmol·m-2·s-1) were used to supplement the light for 5 h(18:00—23:00) to extend the illumination time.When the plant height reached 50 cm,natural light was shaded using black plastic film,and LED light sources with four different R:FR ratios were used to produce short-day treatments.Each LED light source consisted of 360 evenly and proportionally arranged red and far-red LED lamps.The red(R:(660±30) nm): far-red(FR:(730±30) nm) energy ratios of the four experimental treatments were 0.5,2.5,4.5,and 6.5.The LED light sources(50 cm long × 50 cm wide) were fixed 15 cm above the canopy.Each treatment had 30 chrysanthemum plants.All plants were irrigated with a nutrient solution with a conductivity of 1.5 ms/cm(200 μg/g N;80 μg/g P;170 μg/g K).The morphological index was calculated for each plant based on leaf number,plant height,internode length,stem diameter,flower diameter,whole-plant diameter,total leaf area,and dry matter partitioning.The maximum plant leaf number,plant height,stem diameter,flower diameter,leaf area and total dry weight of chrysanthemum occurred at R:FR = 2.5,and the longest internodes were at R/FR=0.5.The relationship between the shoot dry-matter weight per plant and the value of R:FR in all treatments was best described with a exponential-linear model.As the duration of R:FR treatment increased,the shoot and root dry-matter partitioning indices did not significantly differ overall,while the leaf dry-matter partitioning index decreased,the stem dry-matter partitioning index initially increased and then decreased,and the flower dry-matter partitioning index increased.At R:FR=2.5,the chrysanthemum leaf and flower dry-matter partitioning indices were the highest,while the stem dry-matter partitioning index was the lowest;however,the stem dry-matter partitioning index was the highest and the leaf dry-matter partitioning index was the lowest at R/FR=6.5,and the flower dry-matter partitioning index was the lowest at R/FR=0.5.We conclude that increasing the far-infrared component of light was not conducive to increasing flower dry matter,but increasing the proportion of red light can promote stem dry-matter accumulation and a red: far red ratio of 2.5 can improve dry matter transfer into flowers.