Ciclo Di Accrescimento E Differenziazione Delle Gemme in Piante Perenni Nel Territorio Di Bari

Abstract

The secondary wood of the fig tree is characterized by a remarcable degree of dimorphism and the concentric rings d o not correspond to yearly recurring growth periods. These false rings are formed by alternating tangential strips of fibers and wood parenchima. During each vegetative season three or four of these strips arc laid down by the cambium.

During the year the cambium undergoes a period of activity and a period of rest, but there is no histological difference between the early wood and the late one, differentiated just before the restring period. In consequence the so-called annual wood rings do not exist in the fig tree stem.     

Ciclo di Accrescimento E Differenziazione Delle Gemme in Piante Perenni Nel Territorio di Bari

Summary

Growth cycle and buds differentiation in perennial plants growing in Bari's area. — V. The evolution of the wood ring in Rhammus Alaternus L. from December 1946 to March 1949.

In Rhamnus Alaternus L. the cambium awackens in March with the production of an early wood, characterized by large vessels and loose fibers. It keeps on dividing the following months, producing intermediary wood, whose vessels become narrower and narrower. In June the wood ring is almost complete and the cambial activity slows down. In July late wood is formed, with narrow tracheae and highly lignified fibers. From August to February cambial activity is very scarce and irregular, in the wood produced fibers being tangentially compressed.

In a young branch of R. A. cambium becomes suddenly active in February, that is one month before than in the stem, it goes on during the month of March-June, with an evident diminution in the size of the wood elements. This diminution of size instead of being regular, shows some oscillations, expecially during the month of May. In Sept. the cambium starts again dividing, but rather poorly and irregularly, forming some vessels a little wider than the preceeding ones, so that an incomplete false ring is formed only in some points of the branch. As a rule the autumn wood is a typical late wood. This scarce and irregular cambial activity goes on also during Oct.-Dec. In January is more active and forms rather wide vessels in comparison with those formed in the preceeding month. This new formed wood however does not show the characteristics of the early wood of a new ring.

Concluding, the characteristics of the cambial activity of A. R. are

In the stem: 1) March: early wood. 2) March-June: intermediary wood. 3) July: late wood, resting period. 4) At the end of Autumn a scarce production of late wood is sometimes possible.

In the young branch: 1) February: early wood. 2) March-June: intermediary wood, with positive and negative oscillations in the vessels width. 3) At the end of June the late wood is already differentiated. 4) July-August: resting period. 5) Spt.-Juan.: the cambium starts again dividing very scarcely and producing a transition wood between the two rings. This wood can be regarded neither as a true ring nor a false one, it represents rather the last phase of the late wood formation. 6) In the young branch of the female specimen the cambium starts dividing somewhat later than in the male one. 7) The wood ring width does not vary much in relation to the yearly amount of rainfall. The lack of relation between rainfall and ring width is particularly evident in 1948 (a rainy year). The, «Compleasance» of R. A. could show that this species is, in Puglia, in its own habitat. On the other hand it is rather peculiar that R. A. forms only one wood ring during one year, with production of early wood during the spring, and of late wood in the autumn, instead of producing a second autumn ring following a distint summer rest, as could be expected.     

Ciclo Di Accrescimento E Differenzazione Delle Gemme in Piante Perenni Nel Territorio Di Bari

Summary

The evolution of cambial activity during one year in Viburnum Tinus L. in Bari has been studied. The research seems to be particularly difficult in this evergreen shrub. The wood is of the porous diffused type with scarse evidence of wood rings. The vessel diameter varies rather irregularly in the wood ring; on the other side the fibers show wide variations and may be assumed as a good index of the wood ring evolution. Both in the branch and in the stem only one wood ring each year is formed.

Cambial activity prosecutes during the whole year, with an irregular step. During the period July-beginning of September the cambium devides very slowly, or possibly stops deviding.

The early wood is produced earlier in the branch than in the stem; namely in February-end of May in the branch and in March-beginning of June in the stem. The stimulating growth stuffs evidently proceeds downwards from the top to the base of the plant. The relations between ring evolution and climatic factors are discussed. The peculiar cambial poussée during the month of June seems to be correlated with the exceptionally aboundant rainfall of May in Puglia in 1947.

The late wood is formed during the other months discontinuosly. The alternation between the two phases of cambium division and wood lignification has been focussed. The wood ring in Viburnym Tinus is annual and the early wood differentiates in spring.     

L'epoca Della Differenziazione Delle Gemme Fiorali Nell'olivo

Abstract

Calcium, as in general for all plants, is very important for fruit trees and a tight correlation between leaf content and cropping efficiency has been found.

The annual removal of calcium oxide of an orchard has been estimated in kg per hectare: pear 200, apple 180, peach 150, grape 60–130, olive 35–70, kiwi 55–60.

The rootstock affects the calcium uptake from the soil and content of the scion; frequently a higher calcium content is found in trees grafted an dwarfing rootstocks as pear on quince, apple on M9 and M26, peach on Damas.

By the horticultural point of view, calcium is responsible of two main problems: chlorosis due to high active Ca content in the soil and bitter pit, on the apposite, due to a low Ca level in the fruits.

From soil and leaf studies it seems clear that lime-induced Fe chlorosis results from two conditions: a) slow availability of Fe in the soil, and b) immobilization of Fe in the tree in forms that are not available for chlorophyll formation.

Breeding tolerant rootstocks has been the practical solution of chlorosis for most of the susceptible species.

Bitter pit is a physiological disorder of apple fruits, sometime already evident before picking, more frequently after harvesting, during the storage.

The prevention of the disorder is, essentially, a good horticultural practice (pruning, fertilization, irrigation, fruit thinning). Very effective are also Ca sprays as chloride or nitrate, or citrate, or phosphate, starting after setting, 4–5 times every 10–12 days.     

Proposta Di Una Scala Di Differenziazione Delle Gemme Fogliari Del Pioppo Utile Per Gli Interventi Antiparas Sitari

Abstract

A poplar leaf-bud differentiation scale suggested for the pest control treatments. – After having pointed out that also in Poplars the severity of the transplanting crisis and of several pest attacks is in relation to the development stage the leaves are in, the Authors suggest a differentiation scale of the leaf-buds particularly useful for the pest control treatments.     

Variazioni Di Composizione in Piante Di Vicia Faba L. Trattate Con Acido Gibberellico (Nota preliminare)

Abstract

The effects of gibberellic acid on the composition of VICIA FABA. — The A. takes into consideration fresh weight, dry weight, total ash and chlorophyll, carotene, mineral content variations in Vicia Faba L. plants as affected by pure and practical gibberellic acid treatments.     

Accrescimento e rinnovamento strutturale della compatta in ossa sottratte alle sollecitazioni meccaniche

In questa Nota I sono compresi i capitoli relativi alla letteratura sull'argomento, al piano delle ricerche, al materiale e alla tecnica impiegata, ai mutamenti di peso e di forma delle ossa inerti. Nella Nota II saranno esposte le modificazioni di struttura di 2 e di 3 ordine delle ossa immobilizzate e le conclusioni generali.     

Nuove Stazioni di Festuca Laxa Host in Territorio Italiano e Considerazioni Sistematiche Sulla Sua Indipendenza Da Festuca Dimorpha Guss

Abstract

New localities of «Festuca laxa» Host in the Italian territory and systematic considerations about its indipendence from «F. dimorpha» Guss. Some new localities of Festuca laxa are given for the Alps of Friuli (Northeastern Italy), which show that this species takes part also of Italian Flora. Until now it was known only for Austria and Jugoslavia. The paper furthermore deals with some anatomical differences in the leaf — structure of the two fescues, as to see in transections. F. laxa has normally 3 larger vascular bundles, which are wholly enclosed by T-shaped sclerenchyma and 4(8–9) smaller veins, where the sclerenchyma occurs only in the abaxial face of the blade. F. dimorpha on the contrary has 5 larger bundles and usually 6 smaller ones. The number of the secondary veins depends in both cases on the various sizes of the leaves. Also the cenotic and ecological behaviour of F. laxa is shortly illustrated on the basis of two phytosociological records.     

Morfologia e Comportamento Di Due Linee Del Triticum « Denti De Cani » in Relazione al Periodo Di Semina

Abstract

Morphology and behaviour of two lines of « Triticum » « Denti de Cani » in relation to sowing time. – Two lines of Triticum « Denti de Cani » have been studied: it is a 42-chromosome allopolyploid spontaneous in Sardinia. By means of the technique of successive sowing, applied in the years 1964–65 and 1965–66, these two lines – line CP characterized by solid stem (quite solid) and line CV by hollow stem (quite hollow) – have revealed remarkable differences. The sowings, carried out on December 1 and 20, January 10 and 30, February 20, March 10 and 30, have yielded quite different plants both for morphological characteristics and cycle lenght. In particular, hollow stem plants, beginning from January show a delay in the growing, if compared with solid stem ones, and their cycle doesn't come to an end if the sowing is made after the 10th of March. These and other differential characteristics are so clear and marked that it is possible to distinguish the plants of the two lines since the first stages of their development. These two lines seem to have different photothermo-periodical sensitivity: the solid stem line corresponds to a spring or alternative wheat, whereas the hollow stem line corresponds to a winter wheat.