lo Xov., 1909.] Bees and Fruit Fertilization. 693 



BEES AND FRUIT FERTILIZATION.'^ 



R. Beiihne, President of the Victorian Apiarists' Association. 



The blossom of fruit trees consists of the calyx or cup, the sepals or 

 or short green leaves which cover the bud before it opens, and the petals 

 of various shades of white and pink, inside which are the stamens carrying 

 the anthers or male organs producing that extremely fine fertilizing powder 

 called pollen. The stamens, of which there are many in each flower, sur- 

 roimd the pistil ; in the case of the blossom of stone fruit there is one ; 

 in apples, pears, &c., there are five pistils. The upper part of the pistil 

 or female organ, is the stigma, with a duct or passage leading down into 

 the base of the pistil. To produce a fruit it is necessary for a pollen grain 

 to reach the stigma. Pollen grains, though small, are of ornamental 

 appearance, and complex in structure, consisting of an outer and inner cover- 

 ing, the latter enclosing a jelly-like protoplasm containing nitrogen and 

 other chemical matter. Lodged on the stigma, the pollen grain absorbs 

 moisture, swells, and throws out a tube, which grows down the pistil 

 till it reaches the unimpregnated nucleus in the ovule, which is situated in 

 the ovary at the base of the pistil. Thus fertilization takes place. In the 

 case of an apple blossom there have to be '^^^'Q distinct fertilizations corre- 

 sponding to the five divisions of the core, while with the blossom of straw- 

 berries, raspberries, and others over one hundred fertilizations are re- 

 quired. If anv of the pistils fail to receive pollen a deformed fruit re- 

 sults — an apple depressed on one side or berries showing hard, green un- 

 developed places on the ripe fruit. If an apple so deformed is cut cross- 

 wise no pips will be found in the section underlying the undeveloped part, 

 and such apples usually fall before reaching maturity. It is therefore im- 

 portant that a pollen grain should reach each stigma, and that pollen grain 

 should come, not from the anthers of the same flower, but preferably from a 

 flower on another plant of the same species. 



According to Darwin, the cross fertilization of flowers is the most im- 

 portant factor in the continued vitality of any species of plant. In double 

 sex flowers, such as those of fruit trees, self-fertilization is possible. 

 Nature, however, provides devices and conditions to avoid it. The stigma 

 of some flowers does not become receptive till the anthers on the same 

 blossom have shed their pollen, and therefo^^e pollen from elsewhere has to 

 reach the stigma. Some varieties of fruit, such as the Bartlett pear, cannot 

 produce fruit without the pollen of some other variety. Cucumbers, melons, 

 pumpkins, and similar plants have separate male and female flowers, and 

 in all these instances some agency is necessarv to bring the pollen from the 

 anthers of one blossom to the stigma of another. Wind is one of the 

 agents, but the principal ones are insects, and amongst them the most im- 

 portant is the bee. Fertilization bv air currents would probably produce 

 barelv sufficient fruit to pre\ent the extinction of the species, but as in the 

 service of man a hen is expected to lay more eggs than .she could hatch, 

 and a colony of bees to produce more honev than is sufficient for its needs, 

 so a fruit tree is expected to vield more than sufficient for its propagation, 

 and for the profitable culture of fruits the agencv of insects is needed in 

 the fertilization of the bloom. 



The honey bee is not only the most important factor in pollination, 

 but the one insect which bv structure, the nature of its food require- 

 ments and its habits, is best adapted for the purpose. It obtains its food, 

 nectar and pollen from the blossoms of plants. The nectar obtained from 



* Paper read at the Annual Conference of Fruitgrowers helrl at Bendigo, September, 1309. 



