EFFECTS OF CORRELATION BETWEEN VEGETATIVE AND REPRODUCTIVE FUNCTIONS IN THE TOMATO (LYCOPERSICON ESCULENTUM MILL.)

Abstract

IntroductionThat a certain antagonism exists between vegetative growth and reproduction seems still to be the rather prevailing opinion among students of plant development. Luxurious vegetation is thought to be detrimental either to the initiation of gametes or to their union, resulting in a conspicuous absence of seeds and fruit, while a limited vegetative growth is considered to be the precursor of marked reproductive activities. In many instances this apparently is true. The facts, however, do not permit one to accept such a view as an axiomatic generalization, for careful analysis of the development of many plants leads to a diametrically opposite conception.Both empirical and experimental evidence leave one hardly room for doubt that only too frequently a clearly recognizable association does exist between excessive vegetation and lack of fruitfulness on one hand, and diminished growth and abundant seed formation on the other. The question is, however, which in this relationship is cause and which is effect; for our present knowledge of correlation, both quantitative and qualitative, between the various parts or organs of higher plants compels one to accept the existence of a causal relationship.Data may be marshalled showing the effects of growth on reproduction, but there is also ample proof of exactly the reverse situation. Plants belonging to all three groups-annuals, biennials and perennials-supply a large number of examples where it is clearly evident (1) that vegetative growth is almost quantitatively determined by the developing seeds and fruit; (2) that it often decreases at the exact time and in the exact proportion to the amount of flowers formed and seeds set; and (3) that the rate of vegetative growth is controlled by the developing fruit. These conceptions, though quite contrary to a current point of view, do not appear to be overdrawn. Because of the sequence in time, vegetation usually preceding reproduction, and because of the greater economic importance of

Carbohydrate Metabolism in the Tomato Fruit as Affected by Pollination, Fertilization and Application of Growth Regulators

“…One seems to consist of the action of the young fruit in mobilizing reserves in other regions of the plant. The existence of this effect of mnobilization at a distance and its correlativ-e naturie was pointed out by MURNEEK (26) and in its enzymatic aspects, by MAIARRE and by MARRE and BARLASSINA (17,19). But a siml)le mobilization effect, if active in increasing the availability of carbohydrates, does not explain their preferential accumulation in the growing ovary.…”

“…3) or at some distance (26). In this test, older fruits were absent or five to seven fruits approximately three weeks old were present.…”

Experimental Modification of Plant Senescence.

“…Many effects have been observed to follow the removal of flowers. In addition to the deferred senescence (6) there is an increase in growth rate (7), reduction in flower abscission (13), an increase in subsequent fruit set (8), and an extensioni of the duration of flowering (5).…”

Seed Production Affects Maternal Growth and Senescence in Arabidopsis

“…Furthermore, developing offspring and the mother plants should have conflicting interests regarding the production of new reproductive structures. Interestingly, control mechanisms exerted by developing seeds over maternal growth and life span have been observed in plants (Murneek, 1926;Molisch, 1929;Noodén et al, 2003). In legumes such as soybean (Glycine max), for example, both reproductive growth and the onset of leaf senescence are under correlative control (Noodén and Penney, 2001) by developing seeds so that plants grow and live considerably longer when developing fruits are continuously removed (Leopold et al, 1959;Lindoo and Noodén, 1977).…”

“…It has been proposed that growth arrests upon fruit production should be termed "mitotic senescence" as meristematic cells lose the ability to undergo mitotic cell division (Murneek, 1926;Molisch, 1929;Gan, 2003;Noodén et al, 2003). Peas seem to be a good example of such apex senescence as DNA fragmentation (a sign of cell death) was detected in mitotically arrested apices (Noodén and Penney, 2001;Wang et al, 2007).…”