A. V. Varadaraja Iyengar

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A. V. Varadaraja Iyengar

Abstract

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A. V. Varadaraja Iyengar

Abstract

Spike disease in sandal is grouped under virus diseases of plants. It is fatal to sandal. Although little is known of the nature of the virus, considerable information is available about its physiological and pathological effect on sandal, which is a ischolar_main parasite feeding on other plants growing near it. Analysis of the different parts of the plant in health and disease in relation to the make up of the mineral nutrients therein and in relation to the availability of these in the respective soils are reported here. Gradients in respect of the major soil constituents in those plants are also presented. The immediate effect of the virus is traced to the defective functioning of the ischolar_main-ends and haustoria in consequence of which, the intake of the inorganic nutrients is seriously affected and interfered with. A possible mechanism of the differential functioning of the ischolar_mainends and of haustoria is indicated herein. It is found that the host plants supply the sandal only certain nutrients while the soil is the direct source for some others. In effect, lime alone seems to be directly correlated with the incidence and physiology of spike disease in sandal.

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A. V. Varadaraja Iyengar

Abstract

Besides sandal, 37 other plant species have been observed to be spiked in the forest areas in S. India. It appears that all of them could be grouped together under the general and generic name of SPIKE, both on the basis of their morphological characteristics and physiological effects on such plants. A new group is thus included like the MOSAICS, YELLOWS and the like. Although it had not been possible to investigate all of them, the physiological effects on sandal, periwinkle, Z. orenoplia and Dodonea viscosa are reported here. The course of reaction in all of them seems to be identical.

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A. V. Varadaraja Iyengar

Abstract

Spike disease of sandal is an infectious disease, belonging to the group of viruses. Its ready communicability to a healthy sandal in the field and under artificial conditions determines its infectivity which had assumed a high degree of virulence in some years. The loss to the State revenues due to spike is enormous; its supply had been reduced to more than half within the last few years. The present situation, therefore, calls for immediate action by the several States concerned in the industry. That the diseased sandal is the seat and source of infection is fully established here. Hence its eradication at the earliest possible time is effectively pointed out, so as to maintain continuous supply of this important species. A simple, rapid, cheap and economic procedure is outlined here for adoption in practice.

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A. V. Varadaraja Iyengar

Abstract

The first evidence of ischolar_main parasitism in sandal was presented by Scott in 1871. Its significance came to be realised only 30 years later, when the ravages of spike on sandal were very heavy. The earlier researches were directed to detecting haustorial connections made by it on several species growing in the forests. The number had gone beyond 320 today. To some, parasitism in sandal was secondary in character, whereas to many, it was the main channel of nutrient supply for the sandal. The absence of ischolar_main hairs combined with the fact that the ischolar_main of this plant haustorises anything from a pebble to its own ischolar_mains, was sufficient evidence of its obligate parasitic nature. It was understood thereby that the host ischolar_mains furnish all the mineral nutrients to the growing sandal. The absorption was through haustoria formed by the parasite on the host ischolar_mains, for this specific purpose. Experiments conducted to verify this concept have been classified here. The observations and results have been discussed in an appropriate manner. In studying the physiology of ischolar_main parasitism in sandal, the relation between its ischolar_mains and the soils below such sandal with and without haustorial function had been examined, based on the analyses for the mineral constituents in such plants and the soils below them. It is now shown that sandal depends upon the soil below it for two major essential nutrients, viz., lime and potash, being directly absorbed therefrom through ischolar_mainends. The dependence of sandal on its host associates, for its nutrient supply is only partial, being confined to two other major entities, nitrogen and phosphorus. This selective activity of haustoria would at once negative the earlier view that sandal is an obligate parasite. Since the absorption of tbe mineral nutrients by sandal ischolar_mains takes place in 2 ways from 2 different sources, by 2 different methods of extraction by its ischolar_mains, a balanced activity of the two active centres, viz., ischolar_mainends and haustoria is indicated by the ratio Ca/N (Calcium to Nitrogen). Preliminary attempts have been reported here to assess the influence of the host plants on the foliar characteristics of sandal to correlate in the field the possible associates through measurements made on sandal leaves, chemically and biometrically. Whatever is known about the parasitism of sandal today, had been the outcome of researches on spike disease of sandal, and not directly on the physiology of its ischolar_main activity. Based on its primary feature of haustorising the vegetation growing around it, the incidence of spike in sandal was also traced to many host species. This is found to be entirely incorrect. An appendix is included herein, indicating the host plants of sandal so far recorded.

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A. V. Varadaraja Iyengar

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A. V. Varadaraja Iyengar

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A. V. Varadaraja Iyengar

Abstract

The sandalwood tree is the native of East Indian Archipelago, and of India. Since its origin had been recorded as being from the former land, it is known in trade as the East Indian sandalwood. The same name is retained here for the sake of convenience. These are the only two sources for the true sandal, which is botanically known as Santalum album Linn. All other varieties and types do not count, although they may find application in arts and in therapy. The sandal owes its importance to the scented heartwood and the fragrant oil derived from it used in perfumery at present. The wood was purchased in auctions held in Mysore in the earlier days and exported to Europe for being distilled. Later on, the State itself established a distillation plant for securing the oil for export purposes. Since the last 50 years and odd, it had been a Foreign Exchange earner. In the Madras State also, the oil is now distilled by private companies and in the north of India, the oil is distilled from wood purchased in auctions held in the sandal centres of Madras. East Indies had not maintained a regular supply and of late, its output is quite low. Hence, the Indian produce alone dominates the world market. Australia had marketed an oil, after the first World War. It was claimed to have equal characteristics as the sandalwood oil, but it is not sandalwood oil. Other sources for essential oils, which have figured as substitutes to sandal oil are not important. The cost of the wood and the oil had risen quite high of late, with the result that substitutes had been produced. This is mostly through adulteration of the true oil with similar oils or with other undesirable ones. Recently, the production of a purely organic product, known in trade as SANDELA GD (R) has posed a threat to this oil, purely because of its cheapness. A. regards its odour, it is not that of sandal oil. This threat has to be met by increased production of sandalwood whose cultivation is seriously threatened by SPIKE disease, killing sandal of any age and size in a few months, if not in a few weeks. This aspect had been critically studied by the Thacker Committee set up in 1966 by the Indian Government. Unless the spread of disease is systematically checked and the cultivation of sandal ensured on a permanent basis, the future will be more bleak indeed. Considering that an export value of over 1 crore of Rupees per year is involved, an expenditure of at least 5 per cent a year on the control of the disease, in the manner already accomplished and reported, is a productive expenditure only. With more oil produced and posterity ensured for supplies, the price of the oil will be more steady.

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A. V. Varadaraja Iyengar

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