Due to imbalance of macro or micro nutrients, unfavorable environmental conditions or poor growing conditions malformed changes take place in flowers due to poor growth and development which is not suitable for marketing is termed as physiological disorder. In other words we can say non-pathogenic problems due to poor cultural practices, mismanagement, nutritional deficiencies, and adverse climatic conditions for growing cut flowers reduce the consumer acceptability and costs huge loss to producer. Cultivating flowers on scientific lines is important and for this reason management practices and production module plays an important role. Deficiency disorders reflects nutrient deficiency where as others are related to environmental and growing conditions.
Causes of physiological disorders
· Water logging or Drought.
· Excessive heat or cold or Frost.
· Nutrient deficiency.
· Environmental pollutions.
· Poor cultivars.
· Poor Soils.
· Defective management practices.
Mineral nutrition deficiency
Balance of macro and micronutrients plays an important role in quality produce. Optimum nutrients play an important role in growth and development of plant. C, H, O, N, P, K, Ca, Mg, S, Fe, Cu, Zn, Mn, Bo, Mo, Cl, Co and Ni are 18 essential elements including macro N, P, K, secondary Ca, Mg, S and micro(iron, manganese, zinc, copper, boron, molybdenum, chlorine, cobalt and nickel. These all are essential for plant growth and development. Mineral nutrition plays important role in crop production.One nutrient influences uptake and utility of other nutrient.Attractive colour, shape, size and foliage of the plants are the parameters of quality flower and to achieve this mineral nutrition and its optimum dose plays an important role. Three concepts are important to understand including theincrease in growth rate increases with increasing nutrient supply (deficient range where the response is linear), maximum growth rate unaffected by additional nutrient supply (sufficient range) and the fall of growth rate and response becomes negative (toxic range). It can be understood by the following examples:
· High nitrogen level induces copper deficiency.
· Excess potassium helps correcting iron deficiency but induces magnesium deficiency and aggravates born stress.
· Excess of Zinc, manganese and sulphate induce molybdenum deficiency and calcium and magnesium aggravate boron deficiency.
ROLE OF NUTRIENTS
Carbon, hydrogen and oxygen
Structural role being the constituents of carbohydrates, fats and plays a key role in providing energy for growth and development in plants.
Involved in chlorophyll synthesis on which photosynthesis is dependent which ultimately lead to proper growth and development of plant
Poor growth,spindly appearance stem, small leaves,premature leaf fall and root branching restricted, imbalance of root/shoot ratio, leaves show chlorosis evenly distributed and in severe stage necrotic.
Role in energy metabolism, absorbed as dihydrogenphosphate in (H2P-4) or monohydrogenphosphate ion (HPO-4-).
Its deficiencycauses severe disruption of metabolism and development causing abnormalities. Leaves are abnormally small with sharp petiole angles, small twig diameter and early flowering are some of the other symptoms of phosphorus deficiency.
Involved in the movement of carbohydrates, stomatal opening.
Imbalance of Photosynthesis and respiration and Physiologically K-deficiency results collapse of chloroplast and mitochondria.
It is commonly a major cation of the middle lamella of cell walls of which calcium pectate is a principal constituent and Provides mechanical strength to tissue.
Retarded, short, thick andcrooked Root growth.Reduced NO3 and increased absorption of K.
Constituent of chlorophyll .Plants absorb it in the form of Mg++ ion.
Leaves become stiff and brittle ,twisted , leaves fall prematurely.Delayed reproductive phase.
Constituent of sulphur containing amino-acids
Sulphate SO-4-) ion and small amount as SO2 absorbed through leaves.
reduced growthand stem remains thin.Chlorotic symptoms first appear on younger leaves and shortening of inter-nodal length.
Exists several enzymes vlike peroxides, catalase and cytochrome oxidase enzymes,important colour of flower. Deficiency induces Interveinalchlorosis of young leaves.
Responsible for activation of decarboxylase, dehydrogenase and oxidase enzymes and symptoms include chlorotic spot , necrosis of young leaves.
Responsible for activation of dehydrogenease enzymes and symptoms include Chlorosis ,browning of young leaves, dead growing points, distorted blossoms development.
Present in nitrogenease, nitrate reductase enzymes, essential and symptoms include deformation of leaves.
Plays role in osmoregulation and charge compension and helps restricted Wiltingand branched root system.
Essential element as far as nitrogen fixation is concerned.
Essential element as far as functions of several enzymes is concerned.
Zn,Cu,Fe, Mn and Bo are available to plants in soils from acidic to neutral pH but 60 to 70 percent of Indian soils possess pH above 7 I,e alkaline soils where as Iron and manganese are pH sensitive. This indicates that pH of soil plays an important role in absorption of nutrients and subsequent utility by plants.
Organic matter of soil plays an important role in proper growth and development of plant.In this connection use of compost for enriching soil is important as most of India soils are low in organic matter (less than 1 percent).
Soil texture plays an important role in availability of nutrients to plants. This can be understood by the concept of Coarse textured soils and high rainfall which induces boron deficiency leaching. Zinc deficiency is prevalent in sandy soils.
Moisture in soil
Hard soils induce manganese nutrition, excess moisture induces iron deficiency as it causes poor aeration. This indicates that moisture in soils should be optimum so that mobilization of nutrients is ensured.
Pest and disease in root
When roots are damaged by an means or pathogen Iron deficiency is induced and causes poor growth of plant,
Zinc and manganese deficiencies are induced in low temperature and at the same time iron deficiency is caused due to high temperature .
Manganese deficiency is caused by low light intensity whereas boron and zinc deficiency in high intensity light.
(Dr. Nasir Hamid Masoodi, Faculty Divison of Floriculture and Landscape Acrhitechture, SKUAST Shalimar Srinagar)