毛竹茎细胞壁半纤维素多糖的免疫细胞化学定位研究

本文以毛竹(Phyllostachys pubescens)为材料,采用免疫细胞化学标记方法对两种细胞壁半纤维素多糖成分,即木聚糖(Xylan)和(1-3)(1-4)-β-葡聚糖［(1-3)(1-4)-β-glucan］在毛竹茎中的分布进行了观察。结果表明,应用免疫细胞化学方法可以准确、有效地观察这两种半纤维素多糖成分在细胞壁中的分布;木聚糖分布在已木质化的组织细胞的细胞壁中,与细胞壁木质化有密切关系;(1-3)(1-4)-β-葡聚糖在幼竹茎基本组织中分布于短薄壁细胞细胞壁中及长薄壁细胞胞间层,而在老龄竹茎基本组织中,仅分布于短薄壁细胞细胞壁中,而长薄壁细胞细胞壁却无此成分,反映出长、短薄壁细胞细胞壁组成上的差异。     

Highly substituted glucuronoarabinoxylans (hsGAXs) and low-branched xylans show a distinct localization pattern in the tissues of Zea mays L

Polyclonal antibodies which recognized highly substituted glucuronoarabinoxylans (hsGAXs) and low-branched xylans and did not cross-react with each other, were raised in order to examine localization of these epitopes in internodes of maize. Immunofluorescent labeling revealed different pattern between two succeeding developmental stages. The hsGAX epitope was localized evenly in primary walls in all tissue types, and strongly in unlignified secondary walls in phloem. However, lignified secondary walls in protoxylem, parenchyma and a part of fibers were faintly labeled with this epitope. Moreover, the epitope showed limited binding in lignified parenchyma and fiber walls at ultrastructural level. Low-branched xylan epitope was localized evenly throughout lignified walls in all tissue types. This epitope was also localized only in lignified walls of other organs such as leaf, root apex and dark-grown mesocotyl. Low-branched xylans are significantly related to lignification. Localization of hsGAX epitope in their organs was similar to that in internodes. The hsGAX epitope was distributed both in unlignified walls of all tissues and in lignified walls of parenchyma and annular thickening of protoxylem. We propose that hsGAX has separate functions in lignified and unlignified tissues. In conclusion, at tissue level, hsGAX is localized mainly in unlignified walls, and low-branched xylans in lignified walls.     

Immunohistochemical localization of hemicelluloses and pectins varies during tissue development in the bamboo culm

The distribution of hemicelluloses and pectins in bamboo internodes was studied immunocytochemistrically at various stages of development. The ultra-structures of bamboo cell walls have been reported previously at various stages. The internodes were identically classified into three developmental phases: primary wall stage (phase I), unlignified secondary wall stage (phase II) and lignified wall stage (phase III), using the same bamboo culm. (1-->3, 1-->4)-Beta-glucans were distributed in nearly all tissues in an actively elongating stage. Limited amounts of beta-glucans were deposited in primary walls and the middle lamellae, but were limited to the phloem in secondary walls. This suggests that the function of beta-glucans might be different in phloem vis-à-vis other tissues. Highly-substituted xylans were located in nearly all tissues of early phase I, but had disappeared in all tissues immediately prior to lignification. In contrast, low-branched xylan epitopes were present only in the protoxylem in phase I, but were present in all tissues immediately prior to lignification in phase II. In phase III, the epitopes were densely localized in lignified walls, suggesting that the substitution of xylans is closely related to maturation. Methyl-esterified (but not unesterified) pectins were present in all tissues of early phase I. Just before and after lignification, both types of pectins were concentrated in the phloem and protoxylem. Xyloglucans were largely distributed in the phloem and in lignified tissues, suggesting that they might be closely correlated with maturation. This represents the first account of the distribution of hemicelluloses and pectins at the tissue and ultrastructural level in bamboo internodes at various stages of development.     

毛竹竹秆基本组织发育过程中过氧化物酶的超微定位

利用电镜细胞化学技术对毛竹竹秆基本组织发育过程中过氧化物酶进行了细胞化学定位。基本组织细胞过氧化物酶活性由胞间隙处的胞间层开始逐渐向中间推进,同期过氧化物酶体、内质网等细胞器也具有酶活性,随后质膜和液泡膜出现酶反应物。次生壁形成期长细胞壁上过氧化物酶高活性主要集中在次生壁窄层中,以休眠期酶活性最高。随着年龄的增加,长细胞的过氧化物酶活性逐渐降低,九年生长、短细胞的过氧化物酶活性已很弱。短细胞的酶活性始终高于长细胞,细胞壁、质膜、运输小泡膜和纹孔也都具有较高的酶活性。短细胞伸长停止与高过氧化物酶活性有关。过氧化物酶分布和活性并不完全对应于木质素的沉积部位,短细胞的过氧化物酶可能参与了长细胞壁中木质素的合成。     

Immunohistochemical Localization of Hemicelluloses and Pectins Varies During Tissue Development in the Bamboo Culm

The distribution of hemicelluloses and pectins in bamboo internodes was studied immunocytochemistrically at various stages of development. The ultra-structures of bamboo cell walls have been reported previously at various stages. The internodes were identically classified into three developmental phases: primary wall stage (phase I), unlignified secondary wall stage (phase II) and lignified wall stage (phase III), using the same bamboo culm. (1→,1→4)-β-Glucans were distributed in nearly all tissues in an actively elongating stage. Limited amounts of β-glucans were deposited in primary walls and the middle lamellae, but were limited to the phloem in secondary walls. This suggests that the function of β-glucans might be different in phloem vis-à-vis other tissues. Highly-substituted xylans were located in nearly all tissues of early phase I, but had disappeared in all tissues immediately prior to lignification. In contrast, low-branched xylan epitopes were present only in the protoxylem in phase I, but were present in all tissues immediately prior to lignification in phase II. In phase III, the epitopes were densely localized in lignified walls, suggesting that the substitution of xylans is closely related to maturation. Methyl-esterified (but not unesterified) pectins were present in all tissues of early phase I. Just before and after lignification, both types of pectins were concentrated in the phloem and protoxylem. Xyloglucans were largely distributed in the phloem and in lignified tissues, suggesting that they might be closely correlated with maturation. This represents the first account of the distribution of hemicelluloses and pectins at the tissue and ultrastructural level in bamboo internodes at various stages of development.     

Lignification and cell wall thickening in nodes of Phyllostachys viridiglaucescens and Phyllostachys nigra

BACKGROUND AND AIMS: Bamboos are among the most important plants in the world. The anatomical structure and mechanical properties of the culm internode are well documented. Fewer details are available of the culm node. The aim of this study was a topochemical investigation on lignification and cell wall thickening in developing and maturing bamboo nodes. The deposition sequence and distribution of lignin structural units and cell wall thickening in different anatomical regions of the node of Phyllostachys viridiglaucescens and Phyllostachys nigra are discussed. METHODS: Cell wall thickening and lignification are investigated in the outer part of the nodal region and in the diaphragm of developing and maturing P. nigra culms and in maturing culms of P. viridiglaucescens of different age classes. The lignification during ageing was studied topochemically by means of cellular UV microspectrophotometry. A combination of light microscopy and image analysis techniques were used to measure cell wall thickness. KEY RESULTS: The fibre and parenchyma cell wall thickness does not significantly increase during ageing. In the diaphragm, the cell walls are thinner and the cell diameter is larger than in the outer part of the node. In shoots, the lignin content in the epidermis, hypodermis and in both fibre and parenchyma cells of the diaphragm is relatively low compared with older culms. The fibre and parenchyma cells of the diaphragm have higher values of p-coumaric and ferulic acids than fibre and parenchyma cells of the outer part of the node. CONCLUSIONS: It was hypothesized that the combination of more hydroxycinnamic acids and of thinner cell walls in combination with higher cell diameters (lower density and lower stiffness) in the diaphragm than in the outer part of the node may play an important role in the biomechanical function of the node by acting as a spring-like joint to support the culm by bending forces.     

Lignification and lignin heterogeneity for various age classes of bamboo (Phyllostachys pubescens) stems

The lignification process and lignin heterogeneity of fibre, vessel and parenchyma cell walls for various age classes of bamboo stems of Phyllostachys pubescens Mazel were investigated. It was shown that protoxylem vessels lignified in the early stage of vascular bundle differentiation, metaxylem vessel and fibre walls initiated lignification from the middle lamella and cell corners after the completion of vascular bundle differentiation. Most of the parenchyma cell walls lignified after the stem reached its full height, while a few parenchyma cells remained non-lignified even in the mature culm. The cell walls of fibres and most parenchyma cells thickened further during the stem growth to form polylamellate structure and the lignification process of these cells may last even up to 7 years. The fibre walls were rich in guaiacyl lignin in the early stage of lignification, and lignin rich in syringyl units were deposited in the later stage. Vessel walls mainly contained guaiacyl lignin, while both guaiacyl and syringyl lignin were present in the fibre and parenchyma cell walls.     

毛竹地下茎对创伤的反应

研究了在中国最为广泛栽培的毛竹(Phyllostachys edulis(Cart.)H.de Lehaie)的地下茎的创伤反应。创伤后的第1天,在伤口附近没有明显反应;2d之后,创口附近可以观察到生理反应的代谢物,在后生木质部的导管中以及在基本组织细胞的胞间隙出现粘状物质,这些粘状物质具有果胶特性;创伤后1周,创口附近的筛管及基本组织中的短细胞的细胞壁变成木质化。同时,基本组织中的长细胞的内壁出现新的次生壁的沉积;2周后,创伤反应的组织与未受创伤的组织之间的区别变得更加明显;4周后,一些导管完全充满了粘性物质,但没有观察到侵填体。由于细胞壁的木质化及酚类物质的填充,筛管完全失去了功能。对创伤后6周的材料进行观察的结果表明,其创伤反应的范围不再扩展,在创伤组织与未受伤组织之间的基本组织的细胞壁变得相当厚,从而在两者之间形成一道屏障。毛竹地下茎的这种创伤反应与毛竹竹竿的创伤反应基本上是一致的,只是略有不同。     

巨龙竹笋-幼竹期秆形发育的组织解剖学研究

巨龙竹( Dendrocalamus sinicus Chia et J. L. Sun)是云南特有的珍稀木本丛生竹,其秆形分为通直型和弯曲型两种变型。为了揭示巨龙竹不同秆形的组织结构特征,本文通过定点观测0 ~ 49 d的巨龙竹笋和幼竹生长发育状况,并采用石蜡切片技术对笋期0 ~ 45 d内样品的组织结构进行比较解剖学研究。结果显示:(1)巨龙竹在笋-幼竹(0 ~ 49 d)发育期,秆高生长呈“慢-快”的趋势,21 ~ 35 d时弯曲型茎秆开始显现,易于辨别;(2)5 ~ 30 d时,弯曲型茎秆中维管束的发育早于通直型;对比弯曲型茎秆内外两侧维管束,内侧维管束导管内径较小,但纤维鞘中的纤维细胞层数更多;(3)弯曲型茎秆中薄壁细胞的分化早于通直型,20 d后弯曲型茎秆中的薄壁细胞出现明显的可被番红-固绿染色的细胞核,并呈有规律的排列;弯曲型茎秆内侧薄壁细胞稍小于外侧薄壁细胞,但内侧被染色细胞核的薄壁细胞多于外侧。研究结果表明巨龙竹弯曲型茎秆性状在笋期第21 ~ 35 d内即可通过茎秆形态判别,弯曲型茎秆中维管束的发育以及薄壁细胞分化均早于通直型茎秆,同一时期弯曲型茎秆内侧细胞分裂较外侧旺盛、维管束木质化程度更高。     

Immunogold labelling of xylans and arabinoxylans in the plant cell walls of maize stem

Summary— Polyclonal antibodies against 4-O-methyl-glucuronoxylan and α L-1-3 arabinofuranosyl poly-β-d-1-4-xylopyranosyl were raised from rabbits. An immunocytochemical technique was used to localize xylans and arabinoxylans in the plant cell walls of the apical internode of two maize lines of different digestibility. The sclerenchyma, fibres and xylem (lignified tissues) and the parenchyma (non-lignified tissue) were studied. The arabinoxylans were more heavily labelled than the xylans in the lignified tissues of the less digestible maize whereas in the more digestible line the labelling of the two polysaccharides was similar. The xylans and arabinoxylans were localized in the secondary cell wall. In both maize lines, labelling increased from the base upwards of the apical internode, reflecting the changes in growth stage.     

Culm strength of barley : correlation among maximum bending stress, cell wall dimensions, and cellulose content

Grass culms are known to differ in breaking strength, but there is little physicochemical data to explain the response. The fourth internode of four brittle and two nonbrittle barley (Hordeum vulgare L.) strains were used for physical and chemical studies of culm strength. Inner and outer culm diameters of brittle strains (3.6 ± 0.2 and 5.0 ± 0.1 millimeters) were not significantly different from those of nonbrittle strains (3.9 ± 0.2 and 5.2 ± 0.2 millimeters). Maximum bending stress, at which the culm was broken, was 192 ± 34 g/mm² for brittle and 490 ± 38 g/mm² for nonbrittle strains. Wall thickness and cell dimensions of epidermal, sclerenchyma, and parenchyma cells were measured in culm cross sections. The area of cell wall per unit cell area for each tissue was significantly correlated with the maximum bending stress (r = 0.93 for epidermis, 0.90 for sclerenchyma, and 0.84 for parenchyma). Cell walls of brittle culms had 6 to 64% as much cellulose content as those of nonbrittle culms. Maximum bending stress correlated significantly with cellulose content of the cell walls (r = 0.93), but not with the contents of noncellulosic compounds. The lower cellulose content of the brittle culm was significantly correlated with brittleness.     

Localization of cell wall polysaccharides in normal and compression wood of radiata pine: relationships with lignification and microfibril orientation

The distribution of noncellulosic polysaccharides in cell walls of tracheids and xylem parenchyma cells in normal and compression wood of Pinus radiata, was examined to determine the relationships with lignification and cellulose microfibril orientation. Using fluorescence microscopy combined with immunocytochemistry, monoclonal antibodies were used to detect xyloglucan (LM15), β(1,4)-galactan (LM5), heteroxylan (LM10 and LM11), and galactoglucomannan (LM21 and LM22). Lignin and crystalline cellulose were localized on the same sections used for immunocytochemistry by autofluorescence and polarized light microscopy, respectively. Changes in the distribution of noncellulosic polysaccharides between normal and compression wood were associated with changes in lignin distribution. Increased lignification of compression wood secondary walls was associated with novel deposition of β(1,4)-galactan and with reduced amounts of xylan and mannan in the outer S2 (S2L) region of tracheids. Xylan and mannan were detected in all lignified xylem cell types (tracheids, ray tracheids, and thick-walled ray parenchyma) but were not detected in unlignified cell types (thin-walled ray parenchyma and resin canal parenchyma). Mannan was absent from the highly lignified compound middle lamella, but xylan occurred throughout the cell walls of tracheids. Using colocalization measurements, we confirmed that polysaccharides containing galactose, mannose, and xylose have consistent correlations with lignification. Low or unsubstituted xylans were localized in cell wall layers characterized by transverse cellulose microfibril orientation in both normal and compression wood tracheids. Our results support the theory that the assembly of wood cell walls, including lignification and microfibril orientation, may be mediated by changes in the amount and distribution of noncellulosic polysaccharides.     

Developmental changes in cell wall structure of phloem fibres of the bamboo Dendrocalamus asper

BACKGROUND AND AIMS: Bamboo culms have excellent physical and mechanical properties, which mainly depend on their fibre content and anatomical structure. One of the features which is known to contribute to the high tensile strength in bamboo is the multilayered structure of the fibre cell wall. The aim of this study was to characterize the development of the layered structure in fibre cell walls of developing and maturing culms of Dendrocalamus asper. METHODS: Cell wall development patterns were investigated in phloem fibre caps of vascular bundles in the inner culm wall areas of Dendrocalamus asper of three different age classes (<6 months old, 1 year old, 3 years old). A combination of light microscopy and image analysis techniques were employed to measure cell wall thickness and to determine number of cell wall layers, as well as to describe the layering structure of fibre walls. Two-dimensional maps showing the distribution pattern of fibres according to the number of cell wall layers were produced. KEY RESULTS: The cell walls of fibres in phloem fibre caps located in the inner part of the culm wall of D. asper developed rapidly during the first year of growth. Six different fibre types could be distinguished based upon their cell wall layering and all were already present in the young, 1-year-old culm. In the mature stage (3 years of age) the multilayering was independent of the cell wall thickness and even the thinner-walled fibres could have a large number of wall layers. The multilayered nature of cell wall structure varied considerably between individual cells and was not exclusively related to the cell wall thickness. Nevertheless, fibres at the periphery of the fibre bundles and immediately adjacent to the phloem elements exhibited a consistent and high degree of layering in their cell walls. CONCLUSIONS: The multilayered structure of fibre cell walls was formed mainly during the first year of growth by the deposition of new wall layers of variable thickness, resulting in a high degree of heterogeneity in the layering patterns amongst individual fibres. A degree of 'order' in the distribution of multilayered fibres within the caps does exist, however, with multilayered cell walls common in fibres adjacent to phloem elements and around the edge of the fibre cap. These findings confirm the observations, primarily in Phyllostachys viridi-glaucescens. The layering structure was not found to be specifically related to the thickness of the cell wall.     

巨龙竹笋-幼竹期秆形发育的组织解剖学研究

巨龙竹（Dendrocalamus sinicus Chia et J.L.Sun）是云南特有的珍稀木本丛生竹,其秆形分为通直型和弯曲型两种变型。为了揭示巨龙竹不同秆形的组织结构特征,本文通过定点观测0~49 d的巨龙竹笋和幼竹生长发育状况,并采用石蜡切片技术对笋期0~45 d内样品的组织结构进行比较解剖学研究。结果显示：（1）巨龙竹在笋-幼竹（0~49 d）发育期,秆高生长呈"慢-快"的趋势,21~35 d时弯曲型茎秆开始显现,易于辨别;（2）5~30 d时,弯曲型茎秆中维管束的发育早于通直型;对比弯曲型茎秆内外两侧维管束,内侧维管束导管内径较小,但纤维鞘中的纤维细胞层数更多;（3）弯曲型茎秆中薄壁细胞的分化早于通直型,20 d后弯曲型茎秆中的薄壁细胞出现明显的可被番红-固绿染色的细胞核,并呈有规律的排列;弯曲型茎秆内侧薄壁细胞稍小于外侧薄壁细胞,但内侧被染色细胞核的薄壁细胞多于外侧。研究结果表明巨龙竹弯曲型茎秆性状在笋期第21~35 d内即可通过茎秆形态判别,弯曲型茎秆中维管束的发育以及薄壁细胞分化均早于通直型茎秆,同一时期弯曲型茎秆内侧细胞分裂较外侧旺盛、维管束木质化程度更高。     

Ultrastructure of fibre and parenchyma cell walls during early stages of culm development in Dendrocalamus asper

BACKGROUND AND AIMS: The anatomy of bamboo culms and the multilayered structure of fibre cell walls are known to be the main determinant factors for its physical and mechanical properties. Studies on the bamboo cell wall have focussed mainly on fully elongated and mature fibres. The main aim of this study was to describe the ultrastructure of primary and secondary cell walls in culm tissues of Dendrocalamus asper at different stages of development. METHODS: The development of fibre and parenchyma tissues was classified into four stages based on light microscopy observations made in tissues from juvenile plants. The stages were used as a basis for transmission electron microscopy study on the ultrastructure of the cell wall during the process of primary and early secondary cell wall formation. Macerations and phloroglucinol-HCl staining were employed to investigate fibre cell elongation and fibre cell wall lignification, respectively. KEY RESULTS: The observations indicated that the primary wall is formed by the deposition of two distinct layers during the elongation of the internode and that secondary wall synthesis may begin before the complete cessation of internode and fibre elongation. Elongation was followed by a maturation phase characterized by the deposition of multiple secondary wall layers, which varied in number according to the cell type, location in the culm tissue and stage of shoot development. Lignification of fibre cell walls started at the period prior to the cessation of internode elongation. CONCLUSIONS: The structure of the primary cell wall was comprised of two layers. The fibre secondary cell wall began to be laid down while the cells were still undergoing some elongation, suggesting that it may act to cause the slow-down and eventual cessation of cell elongation.     

Temporal and spatial profiling of internode elongation-associated protein expression in rapidly growing culms of bamboo

In natural conditions, culms of developing Moso bamboo, Phyllostachys heterocycla var. pubescens, reach their final height of more than ten meters within a short period of two to four months. To study this phenomenon, bamboo culm material collected from different developmental stages and internodes was analyzed. Histological observations indicated that the development of culm was dominated by cell division in the initial stages and by cell elongation in the middle and late stages. Development, maturation, and aging in different regions of the culm were studied systematically from the basal to the top internode. The four major endogenous hormones, indole acetic acid, gibberellic acid, zeatin riboside, and abscisic acid appeared to strongly influence the cell elongation phase. A total of 258 spots were differentially expressed in culm development. Of these, 213 spots were identified by MALDI-TOF/TOF MS and were involved in many physiological and metabolic processes including carbohydrate metabolism, cell division, cell expansion, protein synthesis, amino acid metabolism and redox homeostasis. These proteins with different expression patterns constructed an ingenious network to regulate the culm development. Developmental stage-specific and internode-specific protein expression patterns were identified. Protein abundance was regulated temporally and to some extent spatially, and the sequential development from base to apex of bamboo culm was implemented by temporal and spatial expression of enzymes. Results indicate that during development energy was mainly derived from sucrose degradation, as photosynthetic capacity was poor. The regulation of anaerobic and aerobic modes of respiration appeared to play an important role in energy generation. This is the first report on proteomic profiling in bamboo and helps in understanding the regulatory processes in developing culms.     

The Anatomical Structure of Culms of Phyllostachys pubescens Mazel ex H. de Lehaie

A culm consists of the rind, basic and vascular systems. The rind system is composed of epidermis, hypodermis and cortex which are of small, thick-walled and well packed cells and mainly functions as an outer wall to protect the culm tissues. The basic system is made up of ground tissue and pith-ring. Pith-ring is the inner wall of the culm consisting of several layers of densely arranged, highly lignified cells. Between the rind system and pith-ring is the ground tissue in which collateral vascular bundles are well embedded. Vascular bund]es are well developed with four fibre caps, two lateral on either side of vessels and two polar, one outside the phloem and the other around the intercellular space. All of them function effectively in fixing the conductive elements in position and strengthening the ground tissue around within the culm wall. Vessels and sieve tubes are of vital importance to bamboo life, but partially blocked and eventually lose their conductivity due to deposition of tylosis that may cause death of the aged culms. All cells are strictly axially arranged within the internodes of culm, but become highly modified in the nodes. During intercalary growth of bamboo shoot the vascular bundles of a sheath are connected with those of the culm periphery and become abscissed off to form a sheath scar around the node after cessation of the growth. Inside the periphery, vascular bundles are variably crooked, branched or reunited in the node which becomes causatively swollen, especially in the joint of side branches. Some nodal bundles bend radially inward to pass into the diaphragm where they are irregularly interwoven within the ground tissue, play an important role in transverse conduction and provide mechanical support of the culm.     

Characteristics of culm structure and carbon and nitrogen concentrations in dead bamboo culms of two Phyllostachys species

The tissue structure of a bamboo stem (culm) differs from that of woody species, exhibiting a large cavity in the internode surrounded by a cortex with high silica concentration. Thus, to obtain an accurate estimation of the necromass, as well as carbon (C) and nitrogen (N) stocks in dead bamboo culms, we examined the basic characteristics of culm structure as well as the C and N concentrations of decomposing culms of Phyllostachys bambusoides and P. heterocycla. We collected dead culms of the two bamboo species from 15 bamboo stands in central and southwestern Japan, and analyzed the relationship between the ratio of wall volume to culm disk volume and culm diameter, as well as the changes of C and N concentrations in dead culms with wall density, which can be used as an indicator of the degree of decomposition. The ratio of wall volume to culm volume tended to decrease with increasing culm diameter for both species. The C concentration did not change, but the N concentration increased with decreasing wall density. The wall density was related to the C/N ratio, which is a chemical parameter of the degree of decomposition. The culm structure should be considered when estimating culm density. The mean C concentration can be used for estimating the C stock of decomposing culms irrespective of decomposition level. N concentration, however, should be determined according to decomposition level for N stock estimation.     

毛竹细胞壁自发荧光的显微荧光分光光度分析

利用冰冻切片、荧光显微镜、显微荧光分光光度计、组织化学等方法,观察分析了毛竹（ＰｈｙｌｏｓｔａｃｈｙｓｐｕｂｅｓｃｅｎｓＭａｚｅｌ）茎不同组织在０．１ｍｏｌ／Ｌ氨水、１ｍｏｌ／ＬＮａＯＨ及过氧化氢／冰醋酸混合液处理前后细胞壁自发荧光变化。毛竹茎所有组织在紫外光激发下均产生蓝色荧光;氨水处理后,所有组织荧光强度增加,富含阿魏酸的组织,荧光颜色由蓝色转变为绿色,荧光发射光谱峰值由４７０ｎｍ移至５１０ｎｍ;ＮａＯＨ处理使所有组织荧光强度降低;过氧化氢／冰醋酸混合液处理后,木质化组织仍保持较强的蓝色荧光,而未木质化的组织荧光消失。结果表明,原生木质部导管在维管束分化早期就已木质化;阿魏酸广泛分布于竹笋各种幼嫩组织中,随着毛竹生长、细胞壁木质化的发展其含量下降。此外,过氧化氢／冰醋酸混合液处理可以有效地区分木质素与结合于半纤维素中的酚酸成分     

相岭山系大、小熊猫主食竹类峨热竹的生长发育与环境因子间的相互关系

1994～1996年,在相岭山系冕宁县治勒自然保护区设点,对大熊猫和小熊猫主食竹类峨热竹与其它环境生态因子间的相互关系进行了长达3a的研究。研究结果表明,峨热竹的生长发育与环境生态因子如海拔、郁闭度、坡度和坡向之间有极其显著的相关关系,环境因子对其株高、基径、密度、发笋率、老笋比例和成竹死亡率等有较大的影响。随海拔高度的增加,竹子变矮变细,老笋比例下降;上层乔木郁闭度增加,竹子变稀,发笋率、老笋比例和成竹死亡率均降低。坡度增大,竹子变稀并且细而矮。阳坡的竹子率发笋高于阴坡。