| Leaf morphological characteristics,including leaf size,ratio of leaf length to width(L/W),density of spinescent teeth on leaf margin,and leaf venation,of 18 species of Berber is were quantitatively and qualitatively investigated,by field population sampling and laboratory analysis.Moreover,leaf epidermal micro-morphological features of the 18 species were studied by using light microscopy and scanning electron microscopy.The main research results were shown as below:(1)The leaf length ranged from 0.47 to 17.61 cm,with the shortest B.hemsleyana(1.15±0.26 cm),and the longest B.iteophylla(8.62±3.00 cm);the leaf width was 0.21 to 3.92 cm,with the narrowest B.taliensis(0.42±0.09 cm),and the widest B.amurensis(1.91±0.57 cm);the ratio of L/W ranged from 1.37 to 26.03,the lowest and the highest were B.anhweiensis(1.74±0.16)and B.insolita(12.78±3.41),respectively.According to the ratio of L/W,three categories were found:(a)L/W greater than 10,just only B.insolita with linear leaves;(b)L/W 5-10,consisting of 5 species,B.iteophylla,B.replicata,B.sanguinea,B.sublevis and B.taliensis,their leaves being linear to lanceolate;(c)L/W 1-5,including the other 12 species,their leaves being obovate or elliptic.The leaf margins showed three types,based on density of spinescent teeth on the leaf margin:(a)entire or nearly so,just only B.dictyophylla;(b)densely toothed,consisting of 7 species,B.amurensis,B.anhweiensis,B.iteophylla,B.jamesiana,B.liophylla,B.paraspecta and B.sublevis.(c)sparsely toothed,including the other 10 species,B.baoxingensis,B.hemsleyana,B.insolita,B.lijiangensis,B.phanera,B.pruinosa,B.replicata,B.sanguinea,B.taliensis and B.verruculosa.Leaf margins of B.taliensis were usually with 1-3(-8)spinescent teeth on each side,occasionally entire,although it was described as entire in both Flora Reipublicae Popular is Sinicae and Flora of China.(2)Leaf venation features of the 18 species were summarized as follows:the primary vein framework were all pinnate;the major secondary vein framework included four types,semicraspedodromous,festooned semicraspedodromous,simple brochidodromous,and festooned brochidodromous;intersecondary veins were widespread;tertiary vein often irregularly reticulate,sometimes percurrent coexisted;areolations were mostly moderate or good developed,seldom poorly developed;freely ending veinlets mostly unbranched or with one branch,rarely branching unequal;marginal ultimate venation were usually looped,seldom absent,incomplete,or spiked.The variation of leaf venation features among species of Berberis could provide evidences for differentiating of some confused taxa.For instance,the major secondary vein framework of B.lijiangensis was festooned semicraspedodromous,while the affinitive B.pruinosa was semicraspedodromous;the major secondary angle to the primary vein was inconsistent in B.lijiangensis,but generally uniform in B.pruinosa;except the pair of acute basal secondaries.(3)Light microscopy observation showed that,outline of the outer periclinal walls of the leaf epidermal cells were regularly or irregularly polygonal,the patterns of anticlinal walls were approximately straight,undulate or sinuous.All the 18 species were hypostomatic,and the stomata were mainly anomocytic,some species had actinocytic and cyclocytic stomata.Outline of the outer periclinal walls,and the patterns of anticlinal walls were different among some species,but consistent within species,thus exhibited important taxonomic value.For instance,outline of the periclinal walls of B.replicata were irregularly polygonal in both adaxial and abaxial epidermis,and its anticlinal walls were sinuous;while in its affinitive B.taliensis,outline of the periclinal walls were regularly tetragonal to hexagonal periclinal walls in both leaf epidermis,and the anticlinal walls approximately straight,or slightly undulate.(4)Scanning electron microscopy observation showed that,outline of the periclinal walls,and the anticlinal walls of the abaxial epidermal cells were obscure in all species,while outline of the periclinal walls,and the anticlinal walls of the adaxial epidermal cells were varied among some species.Cuticular membrane of the leaf epidermis was nearly smooth,with stripes,ridges or papillae;wax ornamentation exhibited considerable diversity,such as platelets,membraneous platelets,rodlets,tubules,dense threads,snow flaked granules,or large granules.Shapes of stomata could be divided into three types:(a)the outer stomatal ledges were flat,without protuberance around stomata;(b)the outer stomatalledges were convex,without protuberance around stomata;(c)the outer stomatal ledges were convex,with protuberance around stomata.The inner margin of the outer stomatal ledges was nearly smooth,or partially notched.Outline of the periclinal walls and the anticlinal walls of the adaxial epidermal cells,shape of stomata,cuticular membrane,and wax ornamentation exhibited high variability,but consistent within the certain taxa.Consequently,these micro-morphological features could provide evidences for differentiating similar species of Berberis.For example,the periclinal walls of adaxial epidermis of B.replicata were convex and papillose,and the abaxial epidermis covered with tubules and large granules;while in the affinitive B.taliensis,the adaxial epidermis was nearly smooth,outline of the periclinal walls and the anticlinal walls were obscure,the abaxial epidermis with dense filiform wax ornamentation,the outer stomatal ledges were convex remarkably with protuberance around stomata. |
PDF Full Text Request