Physiology of pollen

Studies on the generative nuclear division. V. Effect of ageing of pollen grains on the generative nuclear division in Tradescantia paludosa.

“…In fact, in a comparative study on respiration of pollen grains, studied in eleven species of angiosperms, the respira tion rate of the pollen grains of the trinucleate-grain-species (six species) was as high as two to three times fold than those of the binucleate-grain-species (five species), and accordingly, in the formers, nutrition source was comparatively exhausted soon (Hoekstra and Bruinsma 1980). It has been known in Pennisetum typhoideum and Arachis hypogaea that stored pollen grains required comparatively higher con centration of sucrose in the culture medium for successful germination and maximum elongation of the pollen tubes (Johri andVasil 1961, Vasil 1962 In our supplemental studies on storage effect of pollen grains, in Tradescantia paludosa, when they were left in the room, both temperature and humidity were not conditioned, it was observed that; when they were sown at 11:00 a.m., namely 3 hr after collection made at 8 a.m., germination and further growth of pollen tubes occurred apparently similar to that observed in the fresh pollen grain culture sown at 8 a.m., but after 7 hr-storage (sown at 3 p.m.), their vitalities decreased to some extent. This tendency was amplyfied more and more in longer period storage up to 16 hr-storage (sown at 12:00 midnight), in which little or no germination occurred (Kamizyo and Tanaka, unpublished).…”

“…But addition of a suitable concentration of exogenous ATP into the artificial medium has slightly improved the mitotic activity. And furthermore, in both plant species of Lilium longiflorum and Tradescantia paludosa, the mitosis was elated more satisfactorily in the medium supplemented with 10% sucrose than in the medium supplemented with 20% sucrose.It has been well known that artificial storage of pollen grains for a certain time results in erratic germination and destituted elongation of pollen tube in vitro (Johri and Vasil 1961, Linskens 1975). In the course study of pollen tube culture in Tradescantia paludosa, it has been noticed that the ageing of pollen grains affected both viability and mitotic activity of the generative nucleus.…”

“…It has been well known that artificial storage of pollen grains for a certain time results in erratic germination and destituted elongation of pollen tube in vitro (Johri andVasil 1961, Linskens 1975). In the course study of pollen tube culture in Tradescantia paludosa, it has been noticed that the ageing of pollen grains affected both viability and mitotic activity of the generative nucleus.…”

Impact of Boron Nutrition in Fruit Crops

“…Visser (1955) showed that a continuous and ample supply of boron was required for pollen tube growth, and speculated that the boron was complexing with cellular materials during the tube elongation process. Along this line, Johri and Vasil (1961) demonstrated that boron was more critical for pollen tube elongation than for pollen germination. Rapid growth of pollen tube depends on constant fusion of vesicles forming the plasma lemma, and continuous secretion of cell wall material.…”

Endogenous Gibberellins of Pine Pollen

“…lished within the last few years (18,27,43), they mention only briefly the presence and possible roles of growth hormones in pine pollen. However, work with pollen of other plant species strongly implicates auxins, GAs and cytokinins in the germination and pollen tube growth processes (3,4,7,21,28,38,49).…”