Differences in nutrients of the columnar cactus Pilosocereus royenii infected by the parasitic insect Hypogeococcus pungen in the southwest coast of Puerto Rico
Plants are in a constant pressure to survive within an ecosystem. Many interactions can be seen within their below and ground environments that present new pathogens, plant competence and herbivores.The absence or low absorption of nutrients can cause abnormal growth, development and reproduction of the plant. This may be the case of the cactus Pilosocereus royenii, since its nutrition may be affected by the blockage of water and nutrients caused by the parasite Hypogeococcus pungen. The study of the mineral nutrition is an alternative to manage the infection of the cactus by a physiological function, developing strategies for the better absorption of essential nutrients despite the pathogen. The mineral nutrition of P. royenii was studied by obtaining 16 stem tissue samples of 6 inches in length: 12 healthy and 4 infected. These samples were extracted from four different study areas in the southwest of the island, between the towns of Cabo Rojo and Guánica. Other 6 samples of galls from infected individuals were also obtained. Each of the samples were processed for a chemical study to obtain the percentage of each nutrient per proband. It consisted of drying samples, grinding and processing in the chemical laboratory of the USDA in Mayagüez.
Among the nutrients observed in the cactus there was N, K, Ca, P, Mg, Mn, Zn, B, Al and S. It was found that of the eleven elements studied, five were significant (P <0.05) and three were marginally significant (0.10> P> 0.05). The nutrients boron (P = 0.003), aluminum (P = 0.017) and calcium (P = 0.011), among others, gave significant results compared to the tissues studied. During the same experiment the tracking effect per element was analyzed and it showed that there is a significant difference between localities in the micro nutrients: aluminum (P = 0.025) and boron (P = 0.031). Furthermore, there is a significant positive interaction between the location and the mean of boron and zinc. It should be taken into consideration that this data can be affected by various factors such as soil composition, water quality and plant type. It is the first time that this type of study is been done in P. royenii, there is no nutritional value designated for the specie yet. Furthermore, future research will observe how the change in nutrients can affect the plant’s metabolism and compound transport, including soil samples and a trial of fertilizers.