Transfusion Tissue in the Leaves of Thuja orientalis L.

The studies on the development and structure of transfusiontissue in the leaves of Thuja orientalis L. reveal that thetransfusion tissue develops all around the vascular bundle andforms a broad wing-like structure on either side of the midrib,in almost the entire length of the leaf. It extends beyond thevascular strand and reaches the apex where it is reduced considerably. The transfusion tissue in T. orientalis is of complex natureand is composed of living and non-living elements. The formerincludes transfusion parenchyma and albuminous cells while thelatter only the tracheids. Both vary in their size and shapeat various positions within a leaf.     

Preparation of Cuticle-free Epidermal Peels for the Demonstration of Primary Pit-fields

Cuticle-free epidermal peels for the demonstration of primarypit-fields (if any) on the outer surface of the epidermal cells,can be prepared by a chemically controlled process, using 5-10per cent NaOH solution as a macerating medium. Such peels canbe obtained from any desired part of the plant within a periodof a week. The process involves allowing the trimmed piecesof the plant material to stand in the NaOH solution at 50–60°C, until all the cuticular depositions on the outer surfaceof the epidermal cells are dissolved and the unwanted tissuesare sufficiently loosened to allow the easy removal of the epidermis.The separation of epidermis is done by giving moderate agitationsin water during washing or by means of a soft-haired brush undera dissecting microscope. The peels so obtained must be washed thoroughly in water andcan then be stained with bismark brown or iron alum hematoxylln.After dehydration in ethanol, they can be mounted permanentlyin Canada balsam.     

Cell Length Variation in the Secondary Phloem of Dalbergia spp. with Increasing Age of the Vascular Cambium

Cell length variation of sieve tube elements and phloem fibreswas studied in relation to their relative position within thebark in five species of Dalbergia. It was found that in fourout of the five species studied, the fibre elements occurringin the vicinity of cambium are longer than those occurring atthe periphery of the bark. D. latifolia is found to be an exception,since the shorter elements occur near the cambium while thelonger elements are found in the outer regions of the bark inthis species. In all the species fibre length declines markedlyin the middle region of the bark, and this is followed by asudden but temporary rise, except in D. latifolia in which theshortest elements occur both in the middle as well as near thecambium. The cell length variation of sieve tube cells does not followany recognizable trend in any of the species studied.     

Anatomy of the vascular cambium of Acacia nilotica (L.) Del. var. telia Troup (Mimosaceae) in relation to age and season

the majority of fusiform initials are multinucleate, a few having as many as eight nuclei. Their length increases down the stem from the apex, attaining a maximum in the old trunk and declining slightly near the base. The width of the initials exhibits similar variation. In the main trunk, fusiform initials, relatively short at the time of cambial reactivation (April), elongate steadily until July. There is a sharp decline in August/September, the cell length recovering during the winter. Seasonal variation in cell width is inconsistent. Ray cell initials, on the other hand, do not vary much in size. They divide more frequently in the older stem, adding to the size of rays. In young shoots, short and uni- to biseriate rays are most abundant, whereas tall and multiseriate rays dominate the cambial surface in the trunk region throughout the year, with their minimum population in the early phase of cambial activity and the maximum during peak activity. The overall proportion of fusiform initials in the cambial cylinder initially increases with age, from young shoots towards the base, and later becomes more or less constant in the trunk region. Here it remains noticeably high during the active growth period and relatively low for the rest of the year.     

Anatomy of the vascular cambium of Acacia nilotica (L.) Del. var. telia Troup (Mimosaceae) in relation to age and season

the majority of fusiform initials are multinucleate, a few having as many as eight nuclei. Their length increases down the stem from the apex, attaining a maximum in the old trunk and declining slightly near the base. The width of the initials exhibits similar variation. In the main trunk, fusiform initials, relatively short at the time of cambial reactivation (April), elongate steadily until July. There is a sharp decline in August/September, the cell length recovering during the winter. Seasonal variation in cell width is inconsistent. Ray cell initials, on the other hand, do not vary much in size. They divide more frequently in the older stem, adding to the size of rays. In young shoots, short and uni- to biseriate rays are most abundant, whereas tall and multiseriate rays dominate the cambial surface in the trunk region throughout the year, with their minimum population in the early phase of cambial activity and the maximum during peak activity. The overall proportion of fusiform initials in the cambial cylinder initially increases with age, from young shoots towards the base, and later becomes more or less constant in the trunk region. Here it remains noticeably high during the active growth period and relatively low for the rest of the year.