Changes in the magnitude and pattern of translocation of photoassimilated ¹CO in soybean plants following an acute exposure to gamma radiation /

Young soybean plants (Glycine ~. L. cultivar Harosoy '63), grown under controlled conditions, were exposed to gamma radiation on a single occasion. One hour following exposure to 3,750 rads, the mature trifoliate leaf of the soybean plant was isolated in a closed system and permitted to photoassimilate approximately 1-5 pCi of 14C02 for 15 minutes. After an additional 45 minute-period, the plant was sacrificed and the magnitude of translocation and distribution pattern of 14C determined. In the non-irradiated plants 18~ of the total 14C recovered was outside the fed leaf blades and of this translocated 14c, 28~ was above the node of the fed leaf, 38~ in the stem below the node, 28~ in the roots and 7~ in the petiole. As well, in the irradiated plants, a smaller per cent (6~) of the total 14 C recovered was exported out of the source leaf blades. Of this translocated 14c , a smaller per cent (20~) was found in the apical region above the node of the source leaf and a higher per cent (45~) was recovered from the stem below the node and in the petiole (11~). The per cent of exported 14 C recovered from the root was unaffected by the radiation. Replacement of the shoot apex with 20 ppm IAA immediately following irradiation, only J partially increased the magnitude of translocation but did completely restore the pattern of distribution to that observed in the non-irradiated plants. From supplementary studies showing a radiationinduced reduction of photosynthetic rates in the source leaf and a reduction of the cumulative stem and leaf lengths in the apical sink region, the observed effects of radiation on the translocation process have been correlated to damage incurred by the source and sink regions. These data suggest that the reduction in the magnitude of translocation is the result of damage to both the source and sink regions rather than the phloem conducting tissue itself, whereas the change in the pattern of translocation is probably the result of a reduced rate of 14C-assimilate movement caused by a radiation-induced decrease of sink metabolism, especially the decrease in the metabolism of the apical sink.

The waning of the two giants: the electoral decline of the Italian Christian Democratic Party and the Italian Communist Party

Italy is currently experiencing profound political change. One aspect of this change involves the decline in electoral support for the Italian Christian Democratic Party (DC) and the Italian Communist Party (PCI), now the Democratic Party of the Left (PDS). Signs of the electoral decline of both parties began to appear in the late 1970s and early 1980s and accelerated in the late 1980s and early 1990s. The pr imar y purpos e of th is thes is is to expla i n the electoral decline of the DC and PCI/PDS in the last decade. The central question being addressed in this thesis is the following: What factors contributed to the decline in electoral support for the DC and PCI? In addition, the thesis attempts to better comprehend the change in magni tude and direction of the Italian party system. The thesis examines the central question within an analytical framework that consists of models explaining electoral change in advanced industrial democracies and in Italy. A review of the literature on electoral change in Italy reveals three basic models: structural (socioeconomic and demographic factors), subcultural (the decline of the Catholic and Communist subcultures), and pol i tical (factors such as party strategy, and the crisis and collapse of communism in iv Eastern Europe and the former soviet Union and the end to the Cold War). Significant structural changes have occurred in Italy, but they do not invariably hurt or benefit either party. The Catholic and Communist subcultures have declined in size and strength, but only gradually. More importantly, the study discovers that the decline of communism and party strategy adversely affected the electoral performances of the DC and PC!. The basic conclusion is that political factors primarily and directly contributed to the decline in electoral support for both parties, while societal factors (structural and subcultural changes) played a secondary and indirect role. While societal factors do not contribute directly to the decline in electoral support for both parties, they do provide the context within which both parties operated. In addition, the Italian party system is becoming more fragmented and traditional political parties are losing electoral support to new political movements, such as the Lega Nord (LN-Northern League) and the Rete (Network). The growing importance of the North-South and centre-periphery cleavages suggests that the Italian party system, which is traditionally based on religious and ideological cleavages, may be changing.