PATTERNS OF GROWTH IN BIRDS. II. GROWTH RATE AND MODE OF DEVELOPMENT

This analysis was initiated to examine the relationship between the rate of growth in birds and their development of mature function. The literature was surveyed for data on growth and development, and the growth curves of 81 species were chosen for the analysis. Growth curves of most species were fitted with the Gompertz equation, and the rate constants of the equation were used as an index of the growth rate. For those species whose curves were fitted better by other equations, with a slightly different form, appropriate conversion factors, derived in this paper, were employed.
Among species with similar modes of development, growth rate decreases with increasing body weight in an allometric manner, with slopes of –0.26 to –0.42, depending on the group. Between groups, the rate of growth in body weight was found to be closely associated with the rate of development of function, in particular, the acquisition of flight. Among those species that can walk at an early age, but acquire flight relatively late, the rate of growth depends primarily on the relative size of the musculature of the lower extremities.
Data are presented to refute the hypotheses that growth rate is adjusted to nestling mortality, or that the energy requirements of the young (and hence their growth rates) are balanced against brood size. It is concluded that most species grow at some physiologically maximum rate, but as yet it is not possible to distinguish between limitation of growth rate at the level of the organism or at the level of the tissue.     

鱼类生长和生长激素分泌活动的调节（综述）

本文综述近十年来在鱼类生长激素分泌和鱼体生长的神经内分泌调节方面取得的研究进展,阐明脑（各种神经内分泌因子）－脑垂体（分泌生长激素）－肝脏（产生类胰岛素生长因子）轴调控鱼类生长的作用,并在此理论基础上提出可供养鱼生产实践应用的基本途径。     

GENETIC AND HORMONAL REGULATION OF GROWTH,FLOWERING, AND SEX EXPRESSION IN PLANTS

The interaction of the genetic and hormonal regulation of growth, flowering, and sex expression in plants is discussed. The genetic control of these processes is characterized, and data on their hormonal regulation are supplied. The interaction of genetic and hormonal regulation is considered with reference to tall-growing and genetic dwarf forms of the pea and wheat plants. It is shown that in the dwarf forms of the pea plant and in many other varieties, growth stimulation in response to treatment with the phytohormone gibberellic acid is clearly manifested and the expression of genetic dwarfism is eliminated, whereas in dwarf wheats it is expressed only slightly, if at all. At the same time both tall-growing and dwarf forms of both pea and wheat show a clearly defined growth retardation response to treatment with the growth inhibitor, abscisic acid, which causes the expression of physiological dwarfism. The short- and long-day characteristics of the photoperiodic response of plants are described as genetically controlled features, and data are given on the induction of flowering of a long-day variety coneflower grown under short-day conditions with the aid of gibberellins extracted from leaves of long-day vegetative plants of short-day Mammoth tobacco. Data are also supplied on the induction of flowering of a short-day variety, red-leaved goosefoot, grown under continuous light with the aid of metabolites extracted from leaves of the same Mammoth tobacco plants flowering under short-day conditions. This demonstrates the possibility of hormonal regulation of the genetically controlled long-day and short-day characteristics in photoperiodically sensitive plants. Genetic and hormonal regulation of sex expression in two dioecious plants, hemp and spinach, is discussed. It is shown that sex expression in these plants is regulated by gibberellins which are synthesized in leaves and cause male sex expression and by cytokinins which are synthesized in the roots and cause female sex expression. These data indicate that sex expression in dioecious plants is the result of interaction between the genetic apparatus and phytohormones.     

ORIGIN,DEVELOPMENT, AND GROWTH OF DIFFERENTIATING TRICHOBLASTS IN ELODEA CANADENSIS

Root hairs of Elodea canadensis develop only from cells which undergo a particular series of developmental steps. These cells, the trichoblasts, are formed as the smaller, proximal product of an asymmetric division, and immediately enter a prolonged phase of synthesis. Histochemical tests show that large amounts of RNA and protein accumulate in the vastly enlarged nucleolus and cytoplasm, while histone increases in the enlarging nucleus. Cytophotometry shows that DNA in the nucleus reaches polyploid levels. Throughout the synthetic phase, almost to the point of root hair initiation at 9.5 mm proximal to the meristem initials, vacuolation is delayed and the trichoblasts elongate less extensively. All results suggest that this synthesis is the type which normally follows cell division, but is greatly enhanced in the trichoblast. In contrast, the initially larger atrichoblasts only accumulate RNA, DNA, and protein in the region from 1 mm to 2 mm proximal to the meristem tip, and they then enter a phase of extensive vacuolation and elongation.     

GROWTH, AND ANNUAL CYCLES IN WEIGHTS, PLUMAGES AND REPRODUCTIVE ORGANS OF GOOSANDERS IN EASTERN CANADA

A study of Goosanders, in connection with a Fisheries shooting programme on Cape Breton Island, has shown the pattern of growth in young birds, and of plumage and other annual cycles in fully grown birds. The plumage cycles show little difference between the sexes in the first year, with males thereafter moulting about one month earlier than females. Virtually no moult occurs from January to March, nor in adults during April to mid-June, in this area. Weights and measurements permit ageing of flightless young of known sex, and sexing of all fully grown birds, but they do not distinguish first-year from older individuals. Gross examination suggests that males in the second calendar year (11 to 12 months old) may come into reproductive condition, at least under conditions of year-round hunting. Variations in annual moult cycles may be due to differing geographic origin of the birds; I suggest that birds killed in other Goosander shooting programmes should be used for comparative studies parallel to this one.     

水螅的消化,排遗和触手生长模式的研究

用中性红标记水螅饵料、手术触手及组织切片等方法，研究水螅的消化、排遗和触手生长模式。结果表明：１．水螅在消化期间常出现纵向收缩运动和局部横向扩张运动，运动方式特点与腔肠的消化、物质输送及排遗机能相适应。２．触手腔食物泡残骸逐渐贮存于触手腔顶端，待顶端衰老死亡组织破裂时喷出体外。３．沿触手近端至远端，组织摄取养料的机能呈梯度衰退；组织生长速率亦呈梯度减慢，直至解体。触手组织不断生长，推移，衰老死亡组织间断地在顶端脱落。４．在良好的营养条件下能人工产生畸形触手。     

INFLUENCE OF SALINITY AND TEMPERATURE ON GROWTH AND PHOTOSYNTHESIS IN THE EXTREMOPHILIC CHLOROPHYTE,NANNOCHLORIS SP.

Major, K. M. & Henley, W. J. Department of Botany, Oklahoma State University, Stillwater, OK 74078-3013 USA Preliminary data suggest Nannochloris sp., isolated from the Great Salt Plains National Wildlife Refuge, is a true extremophile. This alga is able to withstand salinities ranging from 0 to 150 ç and temperatures up to 45°C. To test the hypothesis that acclimation to high salinity confers tolerance to high temperature, experimental cultures were acclimated to salinities of 25 and 100 ç and/or temperatures of 23 and 38°C; irradiance (500 mol photons m^-2 s^-1) was saturating for both growth and photosynthesis. Cells acclimated to low salt and low temperature exhibited high photosynthetic performance in terms of both light-saturated photosynthesis (P_max; 45.0 fmol O₂ cell^-1 h^-1) and light-harvesting efficiency (0.103 fmol O₂ cell^-1 h^-1/mol photons m^-2 s^-1). However, high-salinity cells exhibited values for net P_max (18.1 fmol O₂ cell^-1 h^-1), (0.107 fmol O₂ cell^-1 h^-1/mol photons m^-2 s^-1) and growth rates (ca. 0.4 d^-1) that were equal to, or higher than, those of low-salinity cells when acclimated to high temperature. Both the amount of light required to achieve net photosynthesis (I_c) and that required to achieve light-saturated photosynthesis (I_k) were lower in high-salinity cells than those exhibited by low-salinity cells grown at high temperature; reductions in I_c and I_k were primarily due to increases in light-harvesting efficiency. We propose that an increase in growth temperature might release Nannochloris sp. from energy constraints associated with osmolyte production and low-temperature effects on enzyme activity. These data are consistent with effects of short-term temperature stress on Chl a fluorescence kinetics in this alga.     

半乳糖寡糖在体内和体外对双歧杆菌生长的影响

目的:利用固定化产β-半乳糖苷酶的嗜热脂肪芽孢杆菌连续合成的产物。方法:经柱层析分离纯化得到了纯半乳糖三寡糖和半乳糖四寡糖,用于体外双歧杆菌培养和动物试验。结果:证实了半乳糖寡糖能高效、专一地促进双歧杆菌的生长繁殖。结论:半乳糖寡糖具有改善小鼠肠道内菌群分布,降低小鼠盲肠内pH值的生理功能。     

Cln3缺失对酿酒酵母生长的影响

Cln3是酿酒酵母G1期周期蛋白中的一种,为了研究Cln3在细胞周期与形态发生中的作用,我们构建了酿酒酵母CLN3基因的缺失株,并对其表型进行了分析。结果显示,cln3缺失株对α信息素的敏感性增强,α信息素诱导的细胞周期停滞现象明显大于野生型菌株,这种增强作用不受Sgv1因子的影响。同时,与野生菌相比cln3缺失株的细胞形态也有明显变化,双倍体cln3缺失株细胞的顶端生长能力增强而单倍体细胞的侵入生长能力则受到抑制。结果表明,与酿酒酵母的另外两个G1期周期蛋白Cln1、Cln2不同,Cln3在形态发生中有其独特的功能与作用方式。     

混合培养对光合细菌生长量的影响

采用光合细菌不同菌株,光合细菌株与异养细胞株间混合培养,比较它们与单株培养物生长量的差异。试验结果表明,不同组合的混合培养物春生长量均不同程度高于单株培养物。光合细菌株间混合培养物生长量约高于对照０．３６－１７．４％;多数增长１１％以上。光合细菌株与异养细胞