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Part III. Studies the effect of temperature on the rates of leaf growth and tiller production of Festuca arundinacea. Leaf appearance and primordia production; Leaf length and cell length; Lamina width and area.

Quantitative analyses for total methanol-soluble material, methanol-soluble carbohydrates, anthocyanin, chlorophyll, methanol-insoluble nitrogen, saponifiable material, pectin, lignin, hemicellulose, and α-cellulose were made at weekly intervals for the first 6 weeks of the growth of mango leaves. The results show that in the first 4 weeks, when the leaves contain anthocyanin, production of photosynthetic carbohydrates was low, and lignin and cuticle syntheses were virtually absent. The increase in rigidity of the mango leaf between the second and fifth weeks was significantly correlated with an increase in the hemicellulose content of the leaf. [ABSTRACT FROM AUTHOR]

Studies of attached and detached leaves of Euphorbia caducifolia, the latter collected from morphologically different plants, suggested that this species exhibited typical crassulacean features of acid metabolism. Fluctuations in acidity were found to be due mostly to the appearance and disappearance of malic acid in dark and light respectively. Deacidification also took place when leaves were kept in dark for a longer period. The TAN showed a fall when the leaves aged and were about to fall. A remarkable feature found in this species was the high percentage of total acids which ranged up to 8240 mg/100 g fresh weight of leaves, together with great differences in the constituents analysed. This suggests that morphological diversity is correlated with physiological diversity. [ABSTRACT FROM AUTHOR]

Describes a liquid displacement method for measurement of leaf volume and its use in studies of leaf growth. Description of the apparatus used for the measurement; Possible estimation of mean leaf thickness and air space with the use of the measurement method; Use of the volume measurement to identify the gross morphological characteristics of the leaf.

Focuses on a study conducted on the growth of Italian ryegrass in New Zealand. Description of methods applied by researchers for conducting the study; Comparison of the mean radiation values with those of Great Britain; Seasonal changes in the interval between the appearance of successive leaves; Graphical representation of the dimension of mature leaf laminae; Decline in the number of live tillers in five months.

Examines the impact of climatic variation on leaf development in forage grasses Lolium perenne and Dactylis glomerata. Climatic races of Lolium perenne and Dactylis glomerata; Influence of temperature and supplementary lighting on leaf expansion; Utility of the pattern of climatic variation in the forage grasses in crop improvement.

The article reports on the study of the results of seasonal changes in the growth and vegetation of seventeen perennial species which include mesophanerophytes and phanerophytes in the savanna site in Nigeria. The study examines the length, number of nodes, number of leaves, and diameter of sucker shoot as well as of mature perennial plants. It demonstrates that perennial plants' growth and vegetation are affected by fire, photoperiod, and rainfall. It also shows that the leaf relative turgidity of perennial plant species differs due to air, soil moisture, and leaf age.

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The photosynthates from leaves from extension shoots may be used either for new growth of the shoot itself, or for growth in other parts of the tree. An attempt has been made to elucidate this problem by determining the content of 14C in long shoots to which 14CO2 was applied either through fully developed leaves at the base, or through very young leaves at the apex. In the case of 14C application at the base, 80 per cent or more of the 14C initially taken up disappears from the shoot, and only a very minor part is translocated upwards in the shoot. When the leaves at the apex are exposed, on the other hand 80 per cent of the 14C absorbed is retained in the leaves and shoot components treated as long as there is still considerable terminal growth taking place, although a small percentage is deposited in the lower parts of the shoot. At the same time, a much higher proportion is incorporated into methanol-insoluble components. As terminal growth decreases, a larger proportion of the 14C activity of the apex leaves also disappears from the shoot. The distribution of activity between the sorbitol, sucrose, glucose and fructose fractions was not significantly different in young and in fully developed leaves. The 14C labelling in the sugar fraction was highest for sorbitol, then sucrose, but decreases with time compared to glucose and fructose. [ABSTRACT FROM AUTHOR]

The life cycle and the reproduction of a species of Acrobeloides were studied in monoxenic cultures of Nigon's agar medium with Escherichia coli as a food organism. The growth of individuals was interrupted by lag or lethargic periods connected with moulting. Temperature influenced the growth rate, longevity, and fertility. The nutrient concentrations used did not influence the generation time but had an effect on the reproductive rate. The maximal number of off-spring was not greatly influenced by the experimental conditions. [ABSTRACT FROM AUTHOR]

Sycamore aphids feed on the contents of sieve tubes in leaf veins. The smallest aphids prefer to settle on the minor veins of small leaves, but larger aphids select larger veins. On large leaves, however, even the adult aphids prefer to settle on the minor veins. Aphids feeding on large leaves are unable to reach the deeper sieve tubes in the thicker part of the main veins as their stylets are too short. However, the length of the aphids' stylets cannot account for the absence of aphids from the lateral veins of large leaves or the distribution of the various instars on the veins of small leaves. The preference shown by art aphid for leaf veins of a particular size is probably imposed on the aphids by the structure and physiology of' leaf veins of different sizes. The outcome of this is that only a pan of a leaf is suitable for colonization by aphids. [ABSTRACT FROM AUTHOR]

This article focuses on carrot motley dwarf virus. A virus disease of carrots that causes serious loss of yield has recently been identified in Great Britain. The vector is the willow-carrot aphid, Cavariella aegopodii; so far it has not been transmitted by any other species of aphid. Cavariella aegopodii is one of the most numerous of spring migrant aphids in Great Britain and often accounts for from 20 to 50 per cent of the total of all aphid species caught on sticky traps in May and June. The virus is similar to beet yellows and barley yellow dwarf viruses in its manner of transmission and effect on the host plant. It yellows and dwarfs the foliage and decreases the growth of the root, probably because it interferes with carbohydrate metabolism in the leaves.