| Perilla frutescens(L.)Britt.,a species of annual herb.In the Chinese herbal medicine Perilla leaves,volatile oil is the main component.The volatile oil of Perilla can be divided into different chemical types according to the main components,such as PA type(main perillaldehyde,which conforms to the Chinese Pharmacopoeia)and PK type(main perillaketone),etc.The preliminary investigation of us found that the domestic PA-type perilla resources are seriously lacking,and it is urgent to plant and promote it.After extensive collection of perilla germplasm resources and preliminary evaluation,it was found that PA-type perilla germplasm was distributed in two types:I-Crispa type and II-Big Crispa type,and the overall yield was low and the quality was poor.This paper continues to evaluate the characteristics of PA-type perilla,such as morphology,agronomic traits,volatile oil quality,and dense planting and propose appropriate yield and quality evaluation characteristics.This study was mainly focused on the following aspects:Evaluation of Morphology and Classification The clustering analysis was carried out with 9 PA-type perilla germplasms,according to the 29 morphology and agronomy traits.The results showed that the classification results were basically consistent with the previous classification based on morphology,and classification based on morphological traits.It is confirmed that the II-Big Crispa type is the main type,and the traits such as plant height,leaf color,leaf margin serration,and grain size are between the Perilla frutescens var.crispa and the Perilla frutescens var.frutescens,and has yield advantage compared with I-Crispa type.Continue,we observe and analyzed the 21 PA-type perilla germplasms(belonging to II-Big Crispa type),with optimized 25 morphological traits(including simplification and increase of some traits).Four groups can be divided,and can be distinguished based on plant height.This type had rich variation and have a large selection space.For application,it is recommended to define this type as PA Transitional type.perilla germplasms,belonging to the I-Crispa type,defined as PA Crispa type.According to the results of the two morphological traits,it is considered that the leaf size,leaf shape,leaf margin,leaf fold should be the key evaluation traits.Evaluation of Yield The correlation analysis was carried out with 9 PA-type perilla germplasms,according to the 29 morphology and agronomy traits.The yield of dry leaves per plant was significantly positively correlated with plant height and number of first and second branch,but not with leaf length,width,ten dry leaf weight and leaf water content.Continue to use 7 PA Transitional type perilla germplasms as material,select plant height,branches,and three types of leaves(including leaf number,leaf weight,leaf yield)for correlation analysis.Leaf yield per plant significantly correlated with the number of middle leaves and the number of small leaves,and the traits significantly associated with these two factors were plant height,number of primary branches nodes,number of secondary branches,and number of secondary branches’ nodes.Leaf yield can be roughly evaluated using a few traits such as plant height,number of primary branches’nodes and number of secondary branches.Choosing tall,branched germplasm can achieve higher leaf yields.Evaluation of Dense Planting Resistance 2 PA Transitional type perilla germplasms were planted at 5 planting densities(D1:2500 plants/667m2,D2:5500 plants/667m2,D3:8500 plants/667m2,D4:11500 plants/667m2,D5:14500 Plants/667m2).A total of 17 traits,including leaf shape,plant type,yield,volatile oil content and composition,were recorded and studied.In the planting density of D2-D5,the leaf are narrow,plant are small,the deciduous leaves are increased,and the leaf yield per plant is low,but the leaf yield per mu increases significantly with the planting density,and is basically stable after reaching D4.In different planting densities,2 germplasms’ number of secondary branches,first section with leaves and plant types are changed,at the same time,dense planting resistance of two germplasms are different.The extraction rate of volatile oil from leaves at planting density D2-D5 was about 0.1%higher than that of D1,and there was no significant difference in the relative content of perillaldehyde,among 5 density.In order to achieve high leaf yield,it is recommended to plant at a density of D4:11500 plants/667m2(plant spacing is 15cm,and row spacing is 40cm);while comprehensive leaf yield and leaf morphology are recommended to be planted at a density of D2:5500 plants/667m2(plant spacing is 30cm,and row spacing is 40cm).Evaluation of Glandular Density The volatile oil in the aerial part of the plant of the Labiatae is secreted from the glandular hairs on the surface,characteristics of glandular hair density can be used to evaluate the volatile oil of PA-type perilla leaves.3 PA Transitional type perilla germplasms were used to observing leaf by transparent method and histochemical staining.Two types of glandular hairs were found on perilla leaves:capitate glandular hairs and peltate glandular hairs.The head of the peltate glandular hairs consists of eight secretory cells,which are densely distributed on the abaxial of the leaf;The capitate glandular hairs are divided into short stalk and long stalk glandular hairs.The head of short stalk glandular hairs consists of 1,2 or 4 cells.The glandular hairs of 1 or 2 cells are mostly distributed in abaxial and adaxial,mesophyll and veins of leaves,and there are more glandular hairs on veins,while the glandular hairs of 4 cells are rare and only distributed in the veins on the adaxial of leaves.The long stalk glandular hairs consist of one or two secretory cells,which only distribute in the veins on the abaxial of the leaf.Studies on histochemical staining show that:only the peltate glandular hairs contain terpenoid.The peltate glandular hairs begin to secrete when the leaves are fully expanded.Therefore,observation the density of the peltate glandular in the abaxial leaf’s middle part when the leaf about to be fully mature is suitable for the evaluation of the volatile oil production of the PA-type perilla.In this paper,the evaluation of morphology,yield composition,planting density,and leaf surface glandular hair of PA-type perilla germplasms were studied.The PA Transitional type perilla were defined,and it is the main morphology type of PA-type perilla,and with a large selection space.The main influencing factors for leaf yield are determined.Proposed the reasonable planting density,at the same time according to the development and secretion characteristics of the peltate glandular,the observation period and location to the evaluation of leaf volatile oil characteristics were determined.According to the above research,the descriptors and evaluation standard for PA-type perilla germplasms planting for leaves were established.It laid a solid foundation for further selection of PA-type Perilla planting for leaves. |
