More in-depth study of plant physiology can help with many elements of agriculture and horticulture and offer solutions that are applicable to both fields. Understanding the physiological processes involved in seed germination, seedling development, crop establishment, vegetative growth, flowering, fruit and seed setting, crop maturity, plant hormone interaction, nutrient physiology, stress (biotic/abiotic) physiology, etc., provides a sound scientific foundation for efficient monitoring and advantageous manipulation of these phenomena.
Plant physiology offers a foundation for improving crop production since economic yield, which is the result of these phenomena, and plant health are what we are interested in in agriculture. Crop physiology is the study of these phenomena with the goal of creating better crop management techniques. The examples below illustrate how vital physiology is to agriculture and horticulture;
1. Seed Physiology
The most crucial ingredient in agriculture is seed. Many internal and environmental variables affect seed germination and optimal seedling establishment.
Understanding the many physiological and morphological changes that take place during germination is made easier with knowledge of seed physiology. Seed dormancy results from any departure from these mechanisms. In intensive agriculture, it’s critical that collected seed not be used right away for the following crop because of the dormant state of the seed. Crop physiologists have developed many techniques for breaking the seed dormancy by studying the origins and effects of this issue. It is advised to treat paddy seeds with either HNO3 or GA the following season when they are utilized as seed material.
2. Optimum seedling growth and plant population
We can obtain the highest plant health, which results from the best plant physiology, by understanding how radicle and plumule emergence works and what each of these organs does. Knowing how much water, nutrients, and sunshine plants need can help us manage the plant population for the maximum output. Plant physiology deals with the internal input-output interactions of plants.
3. Growth measurement of crops
High total dry matter output per unit area is the primary need for increased yields in crops. The optimal leaf area index (Optimum leaf area index) and net assimilation rate are related to high dry matter production. (CGR = LAI X NAR). For greater photosynthesis, pruning operations in horticultural crops like mango are based on this notion of good canopy management.
4. Harvest index
The net result of photosynthesis is the difference between the total quantity of dry matter generated and the photosynthates utilised in respiration. The distribution of dry matter throughout the various plant organs affects the economic yield. Farmers are interested in how total dry matter is distributed throughout the main plant organs because they are more concerned with how it is distributed in relation to economic yield. As the reproductive time is shortened by an excessive vegetative development stage in groundnuts, fewer pods are produced. Therefore, cultivars of groundnut with a somewhat long period of reproductive development are preferred.
5. Mode of action of different weedicides
In contemporary agriculture, herbicides are frequently employed to eradicate undesirable vegetation.
The majority of herbicides—roughly half of the economically significant compounds—act by obstructing the electron flow involved in respiration or photosynthetic processes (ex. paraquat, diuron). When the electron transport is obstructed during photosynthesis, the light reaction is essentially stopped. Since the dark reaction does not occur when the light reaction is interrupted, CO2 is not fixed as a carbohydrate. The weed starves to death as a result.
6. Nutriophysiology
Another crucial subject to comprehend while studying agricultural physiology is nutriophysiology. There are around 17 necessary ingredients for a crop to thrive healthily. Identification of vital nutrients, ion absorption methods, indications of their insufficiency, and remedial actions have all been made easier with the use of nutriophysiology knowledge. Checking the toxicity signs of different nutrients is also helpful. Studying plant physiology can help you fully comprehend how fertilisers are used and how plants consume them.
7. Photoperiodism
Photoperiodism is the term for a plant’s response to the relative lengths of day and night.
This idea was utilised to select cultivars that weren’t photosensitive. Semi-dwarf rice cultivars that have transformed Indian agriculture are photo-insensitive, lodging-resistant, fertilizer-responsive, and high yielding. Rice farming is now possible in non-traditional places like Punjab due to photo insensitivity. These types are the only ones that have made rice-wheat rotation feasible, even in traditional settings.
8. Plant growth regulators
Plants have intrinsic growth control systems that work with very low quantities of chemicals known as phytohormones, plant growth compounds, or plant growth regulators. By administering several hormones at the proper plant height and age, blooming, seed germination, and fruit setting have all been regulated.
9. Because Indian agriculture is primarily rain-fed, it is crucial to produce types that are resistant to drought. Some of the characteristics that were used to breed drought-tolerant cultivars and create effective irrigation management techniques include root zone depth, root density, plant water potential, relative water content, water consumption efficiency, and xerophytic characteristics of leaves (sprinkler and drip irrigation).
10. The most reliable characteristic among several physiological techniques is transpiration efficiency, or water usage efficiency, which is “the quantity of dry matter generated per unit amount of water transpired.” The following model provided by Passioura can be used to describe the significance of water use efficiency (WUE) in determining grain production under water-limited settings.
Yield of Grain = T x TE x HI
T stands for the total transpiration of the crop canopy.
WUE or TE = Transpiration Efficiency
Harvest Index is HI (Economic Fraction of Dry matter)
An analytical technique to choose the genotype with high values of T and TE is provided by this connection.
11. Post-harvest Physiology
Agriculture and horticulture post-harvest losses are quite upsetting to the farming community. The two key elements producing physiological changes that lower the post-harvest quality of grains are moisture and temperature. In order to effectively store grains, moisture content must be managed and low temperatures must be maintained. Horticultural crops experience more post-harvest losses than other types of crops since they are perishable in nature. Example: A technique known as “modified atmospheric storage” was created recently to extend the shelf life of fruits and vegetables after harvest. The use of kinetin can lengthen the shelf life of cut flowers (cytokinin). As a result, the burst of ethylene will be lessened, slowing the rate of senescence.
Thus, a basic scientific foundation for understanding many aspects of metabolism, growth, and development is provided by an understanding of the physiology of agricultural plants. This is crucial for crop enhancement and technological advancement in horticulture and agriculture.
